Using a very gentle cleanser, avoiding granular scrubs that irritate the skin, avoiding eating peanut anything, chocolate and even dairy foods.
I used to use NeoStrata's Toning Solution (not cheap, but an excellent toner compared to other toners out there).
Spot treating breakouts with salicylic acid products or Dermalogica's Sebum Clearing Mask, Benzoyl Peroxide can be effective too.
Keeping your hands off your face, changing your pillowcase every 2 days, and using an oil control lotion on areas of the face prone to being oily like the forehead and nose (I used Mary Kay's Oil Control lotion for years and I still love it!).