What's the best way to get over an ex-girlfriend?

I broke up with my now ex-girlfriend four months ago. To give you some context, it was a short (10 months) but extremely intense relationship in which I also asked her to move into my apartment (big step and a new experience for both of us). What started as a great relationship ended up with countless fights and arguments until it got too much and I had to end it.

As I said, it's been four months and I still have very strong feelings for her. I've dated a bunch of girls since, but still can't get over it. Any advice on how to harden the f*** and move on? Or should I go back and tell her how I feel?

Also interested in some of the funnier experiences/suggestions you had!