What affects your credit rating negativley? Does anyone know how the point values are based?

Well, obviously I know WHAT affects it negativley -slow pay, no pay, being over your credit limit, etc. But, what I want to know is how do the 3 credit agencies ( TransUnion, Equifax, and ? can't think of the other one) put a point values up and/or down on things. For example - let's say you are late on paying your VISA card, by more than a month. So, they report as a ';30 day past due'; How does that affect your credit? Does that reporting cause your score to go down 5 points, 40 points, etc. ? Then, what action brings the score back up, and how many points at a time? Let's say I pay off the entire balance of a credit card, then close out that account... does that raise it up another 10 pionts, or as much as 50 pionts? How long does it take for a bad reporting to ';fall off '; of your credit report. I know that each time a lender ';pulls'; your credit report, that in itself causes your score to drop. I would appreciate hearing from anyone who actually knows FACT regarding this-thanks