I am 17 years old and I have acne. I am looking for some natural prevention methods of acne. No creams or anything. I heard that eating cashews helps prevent acne. Are there any other foods I should eat or other natural methods of prevention?

Okay apparently people are missing your keyword "natural". One method that has always worked for me is apple cider vinegar. I use it as a toner and I also make two beverages a day with it. That really helps keep my skin clean and clear. After about a month it gives your skin a really nice complexion. Here is a article with the recipe and more info.
http://hubpages.com/_SkinHelp/hub/A-Natural-Acne-Treatment