Hello and welcome.
These are just my opinions and suggestions. They are not etched in stone. 
You may get other suggestions and advice. Use what you think will work best for you in your situation.
What many people here do to maximize scoring is to only let one credit card report a small (< 9% of credit limit) balance on their monthly statement and then pay in full before the due date. Let all your other cards always report a zero balance on their statements. That doesn't mean you can't use them. You need to use all of them from time to time to show activity but the key is to time your payments before the statements post so only one card shows a balance.
Have you pulled the free reports you can get at annualcreditreport.com? If not you need to do that and go over each of them carefully and see if there are any errors that need to be corrected. Just don't follow the links for scores; pull the reports only.
Do you have any negative items reporting? Late payments, charge offs, collections, etc.? Those can really drag down your score for a very long time.
How old is your credit length history and AAoA (Average Age of Accounts)? A short credit history can be a detriment to your score but often only time can help that.
I also would suggest not to apply for any more new credit for awhile and let everything age a bit.
From a BK years ago to:
EX - 9/09 pulled by lender 802
EQ - 7/06-663, 3/10-800
TU - 8/10-772
You can do the same thing with hard work