There is no one-time secret trick - it is more of a process of growing your credit. However, there is a technique that can help you to boost your credit in about a year time frame. The hardest part is to pay off all credit card balances.
Here are the steps:
1) Clean up. Close all due payments, pay off credit card balances.
2) Improve the 'types of credit used' part of the score. If all your credit is just credit cards - get yourself an installment loan. There is a lot of 'credit builder' 1-year type of loans on the market.
3) Start working on the 'credit utilization' part of the score. Now you play by new rules: Pay off your balance in full every month. Use only up to 10% of total credit line during the billing cycle. For example, if your total credit limit is $2000, never use more than $200 on the card, if needed, refill the balance several times a month. Never carry a balance and miss a payment. Pay several days in advance.
In less than a year your credit score will be in a good credit territory.