When to up weight

[Adrian7]

BTW, your stats look pretty solid,. Im 20 and can barely bench 170, and I weigh 185. Good job.

[Manmeet Singh]

Thanks alot guys I can see that ive been doing something wrong now...
Usually i will start with something i know i can for sure do the first 10 reps of and then up the wieght each other set buuuut i find that i cant reach the same number of reps as the previous and I start losing form and for example barbell curls i end up putting my whole body into it and its just not pretty...thanks for the advice!