1. If you get a big refund each year, you’re having too much withheld from your paycheck.

In effect, you’re giving the government an interest-free loan.

2. If you have too little withheld, you may be charged an underpayment penalty.

You must pay 90% of what you owe for the tax year by the end of that year or an amount equal to 100% of your tax liability for the previous tax year, whichever is smaller.

3. Not every dollar of your taxable income is taxed at the same rate.

That’s because portions of your earned income fall into different brackets, which are assigned different tax rates. Generally speaking, the first dollar you make will be taxed at a lower rate than your last dollar. Your marginal tax rate is the tax bracket at which the highest (or last) portion of your income is taxed.

4. Your combined tax bracket determines how much tax you’ll owe on income from investments such as CDs and money market funds.

Your combined bracket is the sum of your top (or marginal) federal tax rate and your top state income tax rate. It may be less if you itemize deductions since you will be able to deduct your state income tax on your federal return.

5. If you file your return by April 15, but don’t pay the tax you owe, you may receive a late payment penalty.

The same goes if you file for an extension. An extension only allows you to file your return after the due date. But full payment is still required by April 15. If you make a partial payment by then, you may be charged interest on the amount outstanding.

6. You can reduce your chances of being audited.

One of the best ways is to fill out your return completely, correctly, and on time every year.

7. You should pay estimated taxes if you’re self-employed; expect hefty investment income or profits from a property sale; or if you don’t have enough taxes withheld to cover the taxes you’ll owe on non-wage-related income.

Retirees should also consider paying them if they haven’t opted for voluntary withholding on their pension or IRA payments. Estimated taxes are due four times a year (April 15, June 15, Sept. 15, and Jan. 15).

8. Your adjusted gross income (AGI) is your total income minus certain “above the line” deductions such as deductible IRA contributions, alimony payments, or health savings account contributions.

Your AGI primarily determines whether or not you’re eligible for tax breaks. Almost every break, be it a deduction, exemption, or a credit, has its own AGI limit.

9. Your taxable income is your AGI minus exemptions and deductions.

The less your taxable income, the less in taxes you’ll owe. That’s why it’s in your best interest to take advantage of tax breaks where you can.

10. A credit is better than a deduction.

A credit is a dollar-for-dollar reduction of the taxes you owe. A $100 credit means you pay $100 less in taxes. A deduction reduces the taxes you owe by a percent of every dollar you’re allowed to deduct.

You calculate the worth of your deduction by multiplying your marginal (or top) tax rate by the amount of the deduction. If you’re in the 25% tax bracket, a $100 deduction means you’ll pay $25 less in taxes (0.25 times $100).

Before you shop, conduct an auto-biography.

Hey, wait. Don’t go down to the car dealer and start shopping immediately. Are you sure that the car, pickup, sport utility or van you have in mind is what you really need?

If you rush into a deal without carefully considering how you will really use the vehicle, you could be making a $25,500 mistake, at the average new-car price.

Sure, you want a car that will make you smile. But consider the purpose of most of your driving. Is it commuting? Hauling kids? Weekends? Vacations?

If you drive more than half an hour to work every day, a combination of a comfortable ride and reasonable gas mileage is important. If you frequently drive clients or co-workers to lunch, a sleek coupe won’t be welcoming for whomever has to crawl into the back seat; you need a four-door sedan.

If you frequently haul your kids and their many friends or classmates, a minivan or sport utility with three rows of seats may be essential. If weekend errands involve hauling building materials or large bushes, that same utility or van will come in handy.

Be honest with yourself. What is the largest number of people you carry regularly? What is the biggest pile of gear, luggage or haul from Home Depot that you regularly carry?

Once you have made this practical matchup, however, you still have lots of choices. With careful planning, you can get a vehicle that you need and really want.

1. Insurance costs a lot but having none costs more.

There are sensible ways to save money on insurance, but skipping coverage isn’t one of them. Medical bills from even a minor car accident can deplete your savings – a major illness can push you into bankruptcy.

2. If your employer offers insurance, grab it.

Group coverage, particularly when it’s employer-subsidized, is almost always a better deal than anything you can get on your own, even if you’re young and healthy. If you’re NOT young and healthy, it’s definitely a better deal.

3. Comparing plans is tough but necessary.

Unfortunately, there is no such thing as standard coverage. Benefits and costs vary widely from plan to plan. If you have choices, you’ll have to examine each one closely to find the best deal.

4. The lowest premium isn’t always the cheapest plan.

What your insurance covers is just as important as, and sometimes more important than, what you pay up front. Ultimately, the cheapest plan is the one with the best price for the benefits you’re most likely to use.

5. Even good coverage can have big loopholes.

You can count on your health insurance to cover you for a hospital stay. Most policies cover doctor visits, but benefits for mental health, prescription drugs and dental care are strictly optional.

6. You’ll pay more for freedom.

Plans with the most comprehensive coverage at the lowest out-of-pocket cost require you to use a specified network of hospitals, doctors, labs, and other providers. The more flexibility you demand, the more you’ll pay, in either premiums or co-payments.

7. You can check out networks before signing up.

A growing number of public and private sources compile information on the track records of individual doctors, hospitals, and health plans.

8. You can keep your insurance if you lose your job.

State and federal regulations protect you from losing your health coverage in the event you lose your job. Unfortunately, they offer little protection from high premium costs. However, jobless workers may get help paying for these premiums as part of the economic stimulus bill.

9. Working couples have more to think about.

If you and your spouse both get health insurance at work, you must sort out whether it makes more sense to have two policies or for one of you to cover the other. If you have kids, you need to decide who’s going to cover them.

10. Tax breaks can help.

Ordinarily medical expenses, including insurance premiums, are not tax deductible until they exceed 7.5% of your income. However, if you’re self-employed or your employer offers a flexible spending account, you can get a tax break without meeting the threshold.

1. Saving for your own retirement is more important than saving for college.

Your children will have more sources of money for college than you will have for your golden years, so don’t sacrifice your retirement savings.

2. The sooner you start saving, the better.

Even modest savings can pack a punch if you give them enough time to grow. Investing just $100 a month for 18 years will yield $48,000, assuming an 8% average annual return.

3. Stocks are best for your college savings portfolio.

With tuition costs rising faster than inflation, a portfolio tilted toward stocks is the best way to build enough savings in the long term. As your child approaches college age, you can shelter your returns by switching more money into bonds and cash.

4. You don’t have to save the entire cost of four years of college.

Federal, state, and private grants and loans can bridge the gap between your savings and tuition bills, even if you think you make too much to qualify.

5. With mutual funds, investing for college is simple.

Investing in mutual funds puts a professional in charge of your savings so that you don’t have to watch the markets daily.

6. 529 savings plans are a good way to save for college and they offer great tax breaks.

Qualified withdrawals are now free of federal tax and most plans let you save in excess of $200,000 per beneficiary. Plus, there are no income limitations or age restrictions, which means you can start a 529 no matter how much you make or how old your beneficiary is.

7. Tax breaks are almost as good as grants.

You may be able to take two federal tax credits — the American Opportunity Tax Credit and Lifetime Learning Credit — in the years you pay tuition.

Thinking of negotiating directly with your bank or creditor?

According to a recent article in the New York Times, when banks offer to change the repayment terms or agree to a longer payback schedule, they often still report the new terms to credit bureaus as negative marks…deviations from your original plan.

While a deal may help avoid credit card cancellation or bankruptcy, it will also lead to a sharp drop in the borrower’s credit score for as long as seven years, making it far more difficult and expensive to obtain new loans. The average consumer’s score will fall 70 to 130 points, on a scale where the strongest borrowers register 700 or more.

Any change from the original terms of a credit card are likely to have a negative effect on your credit score. That includes credit counseling, bankruptcy, dealing with creditors on your own, or using a debt settlement company.

When a consumer gets behind the eight ball of debt…their credit score is almost always hurt. But, even a great credit score is useless if your debt-to-income ratio is far too high. For example, a person with a stellar 800 credit score that is in debt up to their ears, say a 70 percent debt-to-income ratio, is unlikely to get a loan because they don’t have enough income left over to reliably make the debt payments.

That’s why DMB Financial focuses first on clearing up your debt-to-income ratio by re-negotiating your existing credit card debts down to less than you owe. Pay those off in 24-36 months and debt-to-income ratio looks much better. Then it’s time to start building up your credit score.

Lending decisions are made in part on credit score, but only in part. Debt to income ratio is another significant factor.

If you’re thinking of dealing with banks directly, make sure get educated first. Part 1 of this series is to let consumers know the truth about what will happen to your credit score…it’s likely to drop another 70 to 130 points!

1. Anyone can call himself a planner.

To avoid amateurs, hire a planner who’s earned special credentials (such as a Certified Financial Planner or Personal Financial Specialist designation) by meeting training standards or having a certain level of experience.

2. Planning is more than investing.

Not all planners offer comprehensive services. Some just give investment advice or focus on one aspect of planning, such as insurance or taxes.

3. Expand your choices.

When hiring a planner, interview at least three pros to find the one who can deliver the services you need and who’s compatible with your style.

4. Personal references are a good place to start – but not the last stop.

A reference from a friend or family member is a great way to search for a financial planner. But make sure you’ve got similar needs as the person who’s giving the referral. Go to groups like the Certified Financial Planner Board of Standards and the Financial Planning Association for additional references.

5. Understand how your planner is getting paid.

The three most common set-ups are: Fee-only, fee-based, and commission-based. Fee-only planners don’t get commissions for the products they sell – fees are for the advice they give. Fee-based planners may receive commission on some products they sell, but most of their money comes from a fee you pay them. Commission-based planners are paid by the companies whose products they sell.

6. Check credentials.

Check to see if a planner’s record is tarnished by disciplinary problems or complaints. Groups that award credentials or state agencies keep tabs on planners and can provide help.

7. Get references.

Ask a planner for two or more of his clients – then follow up and call to find out how a planner performs in specific circumstances, such as during a financial crisis.

8. Express yourself.

The quality of a planner’s advice is correlated to how well he or she knows you. Make sure a planner asks questions about your finances, goals, risk tolerance and philosophy. If they don’t ask, they probably aren’t paying adequate attention.

9. Know what they’re selling.

Find out what financial products a planner sells and how much he or his firm earns for making a sale. Be wary of planners who push one product – say, one family of mutual funds or one kind of insurance – as they may not give you the unbiased or comprehensive advice you need.

10. Know yourself.

The best planner will take his cues from you. Before you hire someone, identify the financial goals you want to meet, your assets and liabilities, your risk tolerance, and investment style. Are you self-directed or do you want specialized help?

The above post is from the CNN Money series called “Money 101.”