Change your pillow cases often!
I read that pillow cases harbour bacteria and using the same one regularly may spread breakouts all over your skin.
To try this out, I grabbed a couple of cheap ones and change them every four days. (I have two pillows, so I use a different side each night of both pillows.) I'm not entirely sure if this is a legitimate claim of spreading breakouts, but it makes a fair point and is always worth a try (: