It's crazy shit man. Some key things to helping your credit score are.
1) Paying your bills on time
2) The amount of debt you're in and how much money you make
3) The percentage of debt you have on a credit card....less than 70% of your max is good. More than 70% makes your score go down.
My advice is to pick a credit card with the highest interest rate, if you have debt on them is to pay one down to less than 70%. And if you don't have 70% try paying one down with a large sum or paying it off completely. That should pick your score up more than six points.