Welcome to the forums!
Lot of questions in your 3 line post 
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Basic credit building is get to 4-5 credit cards, and maybe an installment loan (for completeness), and then never miss a payment, never pay late, and never pay less than the minimum. You likely have some of this already.
If you're sitting with a lot of derogatory marks on your file, I'd highly recommend posting them over in Rebuilding Your Credit as you might be able to get some of them off, or at least you will get advice as to how to attack each one.
Regarding BK: that's a straight financial decision - if you're saddled with a bunch of debt you have no hope of paying off, then do one of the online bankruptcy "Do I qualify?" type sheets and see if it makes sense; often times a hard look and establishing a budget can make things a lot more manageable but there are certainly times where a BK is the right decision. We also have a Bankruptcy board which there's a good amount of information on.
