The first thing you can do is to simply be yourself. If you really want to have a shot at getting your ex back, you need to become the person that the ex was attracted to in the first place. Too many people in this situation would be tempted to act macho or clingy, both of which are terrible things to do that has already expressed her desire to have space from you. You need to act like your own honest self around your ex and make her see the great person that you are. Only when she truly realizes how much she misses having you around will you have a chance at getting her back.
Avoid frequent Contact:
Another good tip for you is that make an effort to have less contact with your ex is better. This is actually another one of those tips that is, counter intuitive for some people. A lot of people would be tempted to try to contact his ex and get into as many situations with her as much as possible in order to have the maximum exposure to her. This is something that is likely to push her out of your life for good. Your ex broke up with you and that means that they voluntarily decided that they wanted space from you. Give them that space and respect their privacy. Be nice. When you do get a chance to see her, maybe she will start to pick up the things that made her want you in the first place.
Move On Slowly:
Another thing that you can do is to move on slowly. What this will do for you is start to put your mind back into healthy mode. Obsessing after an ex is generally not a good idea, especially if she is the one that ended the relationship. Most of the time, she will not come back to you. If you move on slowly and start to realize that there are other fish in the sea, you will be much healthier mentally. That will translate into much more positive body language which in turn will be noticed by your ex the few times that you see her.
Do Not Blow Opportunities:
The thing you cannot undo is to blow up opportunity with your ex by one stupid line uttered in the heat of the moment. If you do those things above, your ex might not start to take an interest in you again. Be yourself, be honest and above all do not pester her. If you suddenly start to become needy and false, your ex will spot the change a mile away and you will destroy all the progress you have made.