1 - First and foremost, what was it that you did in order to cause the break up? Girls do not break up with guys completely out of the blue, so there is probably a really good reason behind the action even if you are not immediately aware of what it is. The first step in this process has to be to figure out what went wrong, whether or not it could have been prevented, and how can you can fix it now that you know what it is.
2 - If the break up with your ex girlfriend was entirely your fault, then the first thing that you need to do to help rekindle things is to let your ex girlfriend know that you recognize what happened, you recognize that it was your fault, and that you are sorry for your actions and the unintended consequences.
3 - You should continue to socialize with other people, even though you are trying to court your ex again. Just because you and your ex are not in contact right now, that does not mean that you need to cut yourself off from the rest of the world. You should date another girl, or at least go out and have some fun with your friends. It may even work to your advantage for you to cause some jealousy in your ex partner if you really do want to get them back.
4 - Show your ex that you have moved on, but you also need to show her that you still care about her. This is the most ideal way to eventually get her back. Let her know that you have not completely moved on, and that you still have feelings for her, and this will make you appear more mature to her, and more desirable as well.
5 - Finally, it is important that you work hard to become friends with your ex again. This will build trust, and will help to make you closer to one another.
Afterwards, you should ask her why you broke up in the first place, but be casual about it rather than appearing desperate. She will either admit that it was a mistake that the two of you broke up, or she will let you know that the break up was for the better. Once you have an answer, you can proceed from there.
These are just the beginning steps in winning your Ex back. They are the initial steps I followed when I lost the love of my life. And frankly these aren't my original ideas. I turned to T 'Dub' Jackson when I had no idea of how to get my true love back.
T 'Dub' authored a simple, down to earth step by step plan called "The Magic Of Making Up". And you know, it worked like magic for us. Now we are more in love than ever.