Some seriously good advice from Bankrate. Especially, don't apply for a lot of cards in one month. I've been burned very hard on this and it took me six months to recover from my impulse to apply for six cards in a week.

Don't apply for more than one or two credit cards at a time. Each inquiry about your credit is included in your credit report. If too many credit grantors inquire at once, they'll all be suspicious of your intentions.
Make it a personal rule not to charge disposable items on your credit cards. Purchases such as food, gasoline and even other debts should be paid for with cash as the purchase is long gone by the time you receive your bill. Who wants to finance a gallon of milk for seven months?
Consider transferring your balance to a lower rate card. If you apply for and accept a lower-rate card, immediately transfer the outstanding balance from your old, higher-rate card. Ask the issuer of the new card if they have actual payment checks that can be sent directly to the old card issuer to pay off your balance. This method can avoid costly cash advance fees.
Make sure the low rate applies to balance transfers.
Avoid cards that charge interest from the date of purchase with no grace period as well as cards that charge interest immediately on a cash advance, plus charge a fee for each cash advance.