Well, a lot of people would tell you exact numbers of how much you should constantly increase and stuff, but my advice would be to increase the weight when you have become completely comfortable with your previous one. If you hang and feel pain, I would not up the weight till I become comfortable with the current weight I hang. Other than this- make sure to do it slowly and steadily and not rush into the big weights (work yourself to the big weights) not to cause an injury. And make sure to warm up, heal expanded and reverse kegel when hanging! That's my 2 cents.
I am no hanger, but that's what I would do if I was you.