Closing credit cards you've paid off doesn't help, unless you have an inordinately high number of open accounts.... like 10+, or 5+ if you're in a lower income bracket. In fact, closing cards that have no balance is very likely to HURT your credit score if you have other cards still carrying balances. It's about utilization of available credit.... you want to have balances of less than 30% of your total available credit, and no single card near its max.
Keeping a balance on a card does not help. The only reason you should use a card for the purpose of improving your score is to keep the credit grantor from closing the account... every few years, some companies will "purge" accounts that have not been used. Why would they want to keep you active and pay to send you statements or new cards every couple of years when they haven't made a penny off you and you never use your card? However, if you use it a few times a year, even if you pay it right off, then you will not be in the 'inactive' list for a credit grantor.
Credit cards count as revolving credit.... consolidation loans count as installment credit, like a home or car loan. They are in different categories. In some cases, having an installment loan can be beneficial, if you have several revolving lines, but not installment lines... it diversifies your credit and looks better to most lenders and improves your score.
However, not all consolidation loans will be guaranteed to have lower interest rates... I got one last year that was about 16%.... virtually the same as the card it was being used to replace. As mentioned above, without collateral, you're likely screwed.
Just have to **** it up and work some OT for a while...