I'm sure you have heard people on some American programmes talking about getting closure from the relationship, I really think this is one of the best ways to get over someone. Seven months ago I really liked someone but due to very strange circumstances I haven't seen them since then and I have honestly thought about it every day and never got over it but I know if I could see them again I would be happy even if they told me they never wanted to see me again. It would stop me wondering about what could have been because I would know it's definetly over. If your relationship wasn't definetly ended I'd recommend finding out where you stand so you don't have to think about it.
Other people's advice here would also work, I suppose a combination of everything will help you forget about them.