Music is a good idea. Listening to sad music will make you more sad. Listening to happy music will raise your mood.

If what you want is really to move on, I recommend writing goodbye letters. Pour your heart and soul out and begin the process of grieving. Remember loss of a relationship is very similar to death. You can use that fact to gain insight.

I personally find a place I can be alone and write my letters. Then I burn or otherwise destroy them without ever sending them. That way my brain feels like what needed to be conveyed has already been conveyed and I can move on. The brain needs to feel like it is done so that you can start thinking of something new.

That's what's been helpful to me at least.