How to prevent Oily face & Pimples?

I used gatsby facial wash and it got worse. Then I stopped and use natural soap, then it stopped but gradually its starting back again. Is it because of oily skin? How to cure? How to prevent pimples? I don't want to experiment brand-wash or cleasers or anything. Just natural or tips? Please, I'm 14, and I'm a guy. I'm in the Philippines, the climate here is unstable, when its hot; it's too hot, and when its cold; it's freezing. Help?