INCREASE THE LENGTH OF YOUR CREDIT HISTORY – It accounts for 15% of your score. Cancelling an OLD card or getting alot of NEW credit within a short time span can hurt your score because it lowers the AVERAGE AGE of your accounts.

KEEP CREDIT BALANCES LOW – Credit use makes up 30% of your CREDIT SCORE. Try to keep the amoutn you borrow below 25% of your AVAILABLE CREDIT. Even if you pay off your credit cards every month, the average balance will still impact your score.

MINIMIZE NEW CREDIT REQUESTS – They account for 10% of your credit score. Every time a potential lender asks for a copy of your credit report, an inquiry is recorded. If you will be applying for a loan in the near future, DON’T apply for ANY NEW credit cards beforehand. You can also ask the three main reporting agencies to stop unsolicited credit offers.

MAINTAIN DIFFERENT TYPES OF INSTALLMENT AND REVOLVING DEBT – About 10% of your score depends on the type of credit used. How you handle revolvng credit (ie: credit cards) carries more weight than how you deal with installment debt (such as car loans and mortgages).

source; My fico. The material is for general informational purpose only.