I had acne when I was a teenager and until my early twenties (until I was prescribed Roaccutane, which sorted out the problem).
Obviously Roaccutane is only for serious cases, but until then I tried everything...the best advice I can give is:
Wash pillowcases and towels very often (every other day if possible)
Keep hair out of the face (and keep hair clean, of course)
Wash face both morning and evening before bed.
Use non-comedogenic but gentle products, the ones that dry out the skin are the worst, it is conterproductive to use those, really...
Use a good moisturizer, when you have acne you tend to go for creams that feel more like a gel because you are scared of using something that feels even a tiny bit greasy, but you really need a cream that keeps your skin moisturized, not dry, because to dry out the skin is also conterproductive. I think Avene is a wonderful brand (Hydrance Optimale cream).
Add a drop or two of pure tea tree oil in the cream before bed (avoid eye area). I tried everything under the sun for acne and I've got to say that tea tree oil is the most effective thing I've ever tried (apart from Roaccutane!), much more than antibiotic creams. I've got quite a good skin now normally, but sometimes prone to have some spots still and nothing beats tea tree oil.