A popular credit urban myth is that by closing credit card accounts, you can boost your credit score.
This isn't the case. By opening a credit card account, the damage has been done. Closing it only furthers the damage. The way to boost credit score is counterintuitive: you have to make small transactions and pay them off. Your credit reporting agency makes no distinction between a $50 payment made on time versus a $5000 one made on time.
Add a couple points to your score the disciplined way and make 50-60 dollars in purchases. Pay them off in FULL so you won't have interest.