What would you do to try to get back with an ex?

I had a girlfriend whom I had an on/off relationship. Basically if she wasn't mad at me, I was mad at her and finally decided not to pursue her anymore a few years back. I feel I'm at a high point in my life and would reconsider taking her back (it was a mutual decision to leave each other alone). Any good suggestions? I found her Facebook page. Sometimes I get angry at what she did to me but then I do miss her being around me because she had that affect. Should I even try?