I have found products with salicylic acid to be very effective in clearing up my acne. I use a toner with 1% salicylic acid (I buy whatever is cheapest, I think they are all pretty much the same) and since I have started doing so, I've had noticeably less problems with acne. I also have found
Biore's pore unclogging scrub to be effective.
When I do get a blemish (which is relatively rare, now that I'm using the combination of toner with salicylic acid and the Biore pore unclogging scrub, I dab a very small amount of
Origin's spot remover on it, and, I kid you not, the blemish is gone by the next morning.
Products with Benzoyl Peroxide have also been recommended to me for treatment of existing acne (such
Neutrogena's On-the-Spot treatment), but I have not found it to be as effective as the salicylic acid products (but everyone's skin is different so they might work for you). And benzoyl peroxide will bleach fabric, so you have to be very careful when using it (be sure wash your hands thoroughly before wiping them on a towel or all your towels will soon have bleach marks).
And friends that have had far more serious acne than me tell me that the Proactiv system may be expensive but it absolutely does work.
Finally, exercise definitely helps. All that sweating clears out your pores. My skin has been noticeably better since I started exercising regularly.