Image: Man paying with credit card © UpperCut Images, UpperCut Images, Getty Images

When it comes to credit cards, you can be your own consumer advocate . . . or your own worst enemy. And these days, this lesson couldn't be more important.

According to TransUnion, one of the major credit-reporting bureaus, the number of new credit accounts grew by 14% in 2011, including subprime credit.

While I'm glad that subprime consumers are able to get back into mainstream credit, be careful. You're likely to get a high interest rate, so don't carry a balance. And I hate to sound skeptical, but even though the Credit CARD Act is in place, there are still plenty of ways for banks to take advantage of consumers.

Since so many people seem to be rediscovering credit cards, it's a good time to look at ways you can protect not only your credit but your hard-earned cash as well.

1. Speak up if you're unhappy

For this to work, you need to stay under your credit card limit and pay your bills on time. Then you'll have leverage when something unpleasant -- like an interest rate increase -- happens. If you get whacked with a high rate and you're an exemplary cardholder, call the issuer and state your case.

Likewise, if your annual fee goes up, call and ask them to waive it. Tell them you've been an outstanding customer. You've got offers from other card issuers who are happy to have your business.

See how this is done? You can always be an advocate for yourself, but this strategy works best if you're a top-notch customer. Speak up and you might be able to keep more of your cash where it belongs: in your pocket.

2. Keep tabs on your credit history

Every year, you can get your free credit report from each of the major credit bureaus -- Equifax, TransUnion and Experian -- on AnnualCreditReport.com.

You want to review the report and look for errors or any signs of fraud. An error can really bring down your credit score, and that will cost you when you apply for a credit card or a mortgage. This is a simple but very effective way to protect yourself when it comes to your credit life. Put it on your calendar, and every four months get a report from one of the bureaus.

To keep tabs on your credit throughout the year, use Credit.com's Credit Report Card for an easy-to-understand overview of your credit standing. (Take this free MSN Money quiz to get a credit score estimate.)

3. Get your credit score

A FICO score is what most lenders use to gauge your creditworthiness, so that's the score you want to look at. You can get your FICO score for $19.95, or you can use other credit-score-monitoring products, but make sure they include a FICO score.

Credit scores go up and down constantly, so keep in mind that you're getting a measure of what your score is at that particular time. Even so, I think it's vital to check your score from time to time. This gives you an idea of your credit range so you know what types of credit cards you should apply for. Your score will get dinged if you repeatedly apply for cards that you can't possibly qualify for.

4. Be aware of the consumer protections your card provides

Many credit cards, especially those in the elite group, like Chase Sapphire Preferred, offer purchase protection and extended warranties. Purchase protection can be a real benefit if your merchandise gets stolen or accidentally damaged.

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Extended warranties on credit cards extend the manufacturer's warranty, which varies by card. It's not unusual for people to buy extended warranties when they already have them via their credit cards. Some credit cards even still offer price protection, but this isn't as common as it used to be.

How do you know what protections you have? They will be listed in the disclosure statements. If you didn't keep them when they arrived in the mail with your card, get online and read the fine print. If you can't find the information about these benefits, call your card issuer and ask.

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5. Know the details of rewards programs

I review tons of rewards programs, and I can tell you that some of them are the pits. Not that the programs don't have great rewards, but they explain it in a convoluted fashion. Sometimes you even have to look at several websites to get the whole picture.

You can search the card name online with something like "rewards program" and see what pops up. Yes, it's tedious, but it helps to know everything about the program so you can take advantage of it. The flip side, of course, is that there are also land mines in the details.

You want to make sure you read everything, because you could find nuggets like "if your card is inactive for 12 months, you'll lose your rewards."

6. Check your credit card statement for errors

You want to look for billing errors and possible fraud and check your balance. If you want to, you can check your account online every day. Should you find a billing error, you're protected by Fair Credit Billing Act. You have to write to your credit card issuer within 60 days of the statement date that contains the error. The issuer must respond within 30 days and conduct an investigation within 90 days. Get more details about what to include in your letter here.

If you don't get an acceptable response from your issuer, file a complaint with the Consumer Financial Protection Bureau. But first you have to try to resolve it with your credit card issuer on your own.

7. Stay safe online

This is more in the area of protecting your identity, but it's also a part of protecting your credit life. Even though credit cards do offer a lot of financial protection against losses as long as you report them quickly, losses can create havoc for you and your credit file when it comes to straightening it all out.

Just take this simple precaution: Make sure you see "https" instead of just "http" in the Web address. The "s" indicates a secure site. And make sure you don't give out your card number on sites you're not familiar with or in response to email solicitations.

8. Know the details regarding 0% introductory offers

It might seem odd that I want you to protect yourself against 0% interest rates. But here's the problem -- and I'm talking about both purchase and balance-transfer offers -- it's easy to get blinded by "you pay 0%!" and forget to look at the details.

This can lead to debt, a wrecked credit score and tons of angst in general. Before you grab one of these intro offers, look at the go-to rate. If you're getting 0% interest on purchases for 12 months, you'd better keep track of your balance. Don't wait until the eleventh month to realize that the intro period ends in one month, not in seven months. This situation will be even worse if you've got a $4,000 balance and -- yikes -- you just noticed the go-to rate is 16.99%.

A similar problem occurs with balance-transfer offers. You might feel sure you can pay the balance off during the 12- or 18-month intro period. But what if you can't? Be sure you can live with the ongoing interest rate (aka the annual percentage rate, or APR) if necessary.

9. Before you travel, alert your credit card issuers

If you're traveling, call your bank so you don't unwittingly trigger a fraud alert on your account. Banks are pretty diligent when it comes to monitoring consumer behavior. If your spending patterns suddenly change, the bank may suspect your card has been stolen.

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And if your card account gets frozen, you'll have to turn to other forms of payment, which could not only get expensive but won't offer the same purchase protections as your credit card does. To be safe, carry two cards with you so you have a backup.

10. Remember that business cards aren't covered by the Credit CARD Act

You know what's interesting? Business cards are making a comeback. In fact, the national average for interest rates on consumer cards is 14.91%. For business cards, it's 13.13%. It's a good time to get a business card, but keep in mind that you don't have the same protections -- from sudden interest rate increases, for example -- that you have with consumer cards.

For those with a thriving business who need cards for employees and who want spiffy management tools, it's hard to pass up these cards. So proceed with caution, and avoid carrying a large balance. Just in case.

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