Start with the factors that impact your score. Then address each item in order of impact. Start here:
http://www.myfico.com/crediteducation/whatsinyourscore.aspx
Payment History is the biggest slice at 35%. Responsible usage over time will build this but you also need to consider whether or not you have any derogs. If you do, make sure you address them first. Visit the Rebuilding subforum.
Utilization (Amounts Owed) is the next biggest slice at 30% and covered above. Your current utilization seems fine. It's under the 30% max. General advice for optimal scoring is to let only one balance report with a utilization of 10% or less and it looks like you're already there. That said, the one balance/10% is usually only of benefit to eke out some additional points when apping.
AAoA (Length of Credit History) is the next biggest slice at 15%. It just takes time to improve this. New accounts will reduce it. That is, unless you have an AmEx membership and can take advantage of backdating. With half of your cards at under 2 months you're going to see a hit here.
New Credit is next at 10% and with those new accounts this one will also just take time to recover from.
Types of Credit is also 10% but it's genereally not worth seeking out installments just for scoring purposes.
@mintons wrote:
Should I just maintain zero balances on all of them?
Nope. There's a hit associated with 0. Aim for 0-10% if you're managing reported utilization.
@mintons wrote:
Carry a balance?
Carrying a balance subjects one to interest and that generally negates rewards. There's no need to carry a balance for scoring purposes. You want to manage reported balances which are entirely different from carried balances. One can not carry a balance and still have a balance report. For most cards balances report at statement end. If you pay prior to statement end you can manage the reported balance. Following up with a payment by the due date will let you avoid carrying a balance.
