Rebuilding credit

Will it affect my credit to lower my payoff amount, if that's possible?

I am attempting to get my fico score up quickly. I know many people will say "it's a marathon, not a race." I understand, but also am wondering what the best ways are to bump it up quickly, even if only a little bit.

I also have a student loan that is close to becoming delinquent because I haven't been able to pay the full amount. How much does that affect your credit?