Credit cards give you flexibility, instant access to emergency funds, and convenience. They can also give you major financial problems if you're not careful. Here are some credit card do's and don't's to help you manage your plastic wisely.

Credit cards, and the substantial lines of credit that come with them, have created a love-hate relationship with consumers ever since their inception. We love how easy the cards make our lives. But we hate them when we misuse them.

To help you get a clear definition of the right and wrong ways to use your plastic, here are a few tips

1. Do use a rewards program

Many credit cards offer a rewards program, in which you earn benefits based on how often you use the card. Enroll in one of these programs, and earn the rewards points, but pay the entire balance before the due date. As a result, you won't pay any interest on the balance while pocketing the bonuses.

2. Don't use plastic to pay your tax return

The rewards program doesn't work when it comes to paying your tax bill. If you owe Uncle Sam a hefty sum, you could gain some rewards points by using the plastic. However, the federal government is exempt from paying the 2.5 percent charge levied to vendors by the credit card companies. That means that you'll have to pick up the tab, which cancels out the reward.

3. Do keep your utilization ratio low

If you're going to use credit cards, it's important to consider their impact on your credit score. One factor used to determine it is your utilization ratio. This is the comparison of your credit limit to the amount of credit you're currently using. If you max out your plastic, your utilization ratio will be high, and your credit score will plummet. To keep a healthy number, make sure that your balance stays low.

4. Don't use your credit card to pay student loans

If you're carrying debt from your college days, you may be tempted to switch your balance to a credit card. Many companies offer a zero-percent balance transfer deal: Transfer a balance to their credit card, and you won't pay interest for an introductory period of six to nine months.

You may be tempted to take advantage of the low rate and transfer your student loans. This maneuver works only if you can pay off your loan during the introductory period. If you can't, the zero-percent interest rate will end, and a much higher rate will begin.

A credit card provides you with benefits, like flexibility and convenience, but its instant gratification and tempting credit lines can get you into trouble. Your plastic is a financial tool that needs to be used intelligently. Stick to the rules of sound money management, and your card can be a valuable asset, and not a dreaded liability.