It so comes back to hormones and diet.
I find when I eat lots of processed food or I am about to get my period, I get a break out.
One thing I do is clean my face with Witchhazel each night (you can get it at the chemist for $6 and it lasts for ages. I can't remember what a good brand is called. But I think they are all much of a muchness).
My cousin who had really bad pimples did Pro-Active and had great results.