The one thing I preach when trying to get your ex back, is to treat her exactly like you did in the first place. So many guys start getting a lovey dovey and "I miss you" and stuff, but that's not the way to go. Treat her as if you just met her and shes a new target.
My ex broke up with me recently, about 2 months ago or so. She ended up calling a few days later, we talked, I ended the conversation during a high note. One point for me. A lot of the time I was busy, so when she would call I'd talk for a bit then have to go. She would IM me occasionally, quick conversations, I'd be on my way to go somewhere. She knew that I was hanging out with other girls. She knew that things were happening. I never once told her that I missed her, never once mentioned getting back with her, never once mentioned that we even went out.
Fast forward to last Saturday. She calls, asks to hang out the next day. I tell her I'm working then. She shows up at work. We chat for a little bit, a little kino. She calls me that night to tell me she broke up with her boyfriend. I didn't make a big deal out of it. We hung out the next night, had a friggin' blast at this game place. Bam. Just like that she was mine. She's now calling me frequently. Drives all the way out to my place since I don't drive. Offers to pick me up. Callin' me baby, hun, all that stuff, talking about how shes going to whoop this girl at my work because girls shouldn't "mess with the guy she likes". What did I do to get her back? Same thing I did to get her in the first place. However, she's going to have to work a little bit harder for a second shot. I just haven't let her know that yet
Thats the key, my friend. There is no "secret ex-retreival" formula. It's the SAME thing as you do to a girl in the first place. Never change your MO. Granted, with LTR theres a few more 'tricks' that need to be used, but nevermind those at this moment.