To be able to get back together with your ex girlfriend there are things you need to do and here are some tips:
Do not appear too desperate and needy. Even if you feel desperate and you want to get back together with your ex girlfriend so badly, have power over your emotions and just keep it to yourself.
If you cannot help it then talking to a friend or family is a safe way to cry your heart out. Do not cry or beg with your ex girlfriend present or follow her around. Learn to control your feelings and forget self pity because if you will appear excessively needy and desperate she will get scared and avoid you more.
Keep the communication lines open. Although she ended the relationship, just make her feel that you are civil with her and the communication lines are still open. Of course you do not have to begin the conversation incessantly or call her every minute to let her know that you want her back. But a laid-back hello once in a while is a nice start to somehow still communicate with each other.
Analyze what went wrong in the relationship. Of course there is a problem in your relationship that is why the relationship ended. To be able to get back together with your ex girlfriend, you have to spot the problems, analyze and find solutions. Recall the things that usually end up in arguments, fighting and misunderstandings. Are there needs not met?
Is there something about you that she used to love but somehow you've changed and you no longer have those qualities she finds sweet with you? Maybe you get lost somewhere and deserted the relationship. Knowing what went wrong and how to correct it will be useful for you get back together with your ex girlfriend.