Credit Repair Questions?

I'm almost 26 and have finally gotten a job worth something after being unemployed for almost a year. In this time, I have become late on and defaulted on like 6 credit cards....all of which are glowing red on my credit report right now. I also fell behind on my school loans (this was VERY unwise of me, I know). I'm in the process of paying all these charge offs off, and was wondering how I would go about raising my credit score (currently 518). Once I pay everything off, will my score automatically go up? I know I need to establish a few lines of credit with timely payments of 2 years or more, but alas, I can't get approved for anything! It sucks because with my job now I can afford to pay off the debt AND any new lines of credit.....frustrating......Anyway, any insight would be greatly appreciated!