Following a break up, I know how clueless a guy gets whenever he wonders "How to get my girlfriend back" without losing any pride. Being a guy, and thinking just like how any regular guy thinks, it's not surprising that you constantly philosophize about everything that could have been done differently. I even know of men who put down their prides and start writing apology letters, thinking that it might help them score points with their ex girlfriends. While their ultimate aim is to put their relationships back together, this approach is almost always a dead end because no smart girl is going to fall for it. From your ex girlfriend's point-of-view: "Why only start showing how sorry you are when I already gave you so many chances to do that?"
In all reality, if you honestly owe your ex an apology, then please go ahead and apologize. One simple and sincere apology will suffice and don't expect anything more from her. Don't apologize just for the sake of getting your girlfriend back because you will only be lying to her. Don't apologize if you don't even know what you're apologizing for -- search your conscience and think hard on the areas where you have failed her. Your break up might have occurred because of a specific event or it might have been because of a behavior that your ex girlfriend didn't want to deal with anymore. Whatever it is, if you're still asking "How to get my girlfriend back," then I'm telling you that you need to analyze how you played a part in causing the break up.
This is what I call a reconnect technique. First, you have to connect the dots and see how you played a part in the break up. Then you give your ex girlfriend a call and offer her a sincere apology based on what you honestly felt you did wrong. Do you realize how powerful this technique is? Trust me, your ex girlfriend will feel your sincerity. Not only that, she will also be amazed at how you seem to know what went wrong in the relationship. It shows her, in a subtle way, that you care. This is just the extra boost that you need to win back your girlfriend. Somewhere in her inner conscience, she will think that maybe you do deserve a second chance after all because you actually spent time thinking about the areas where you failed in. You score extra points with her because you know what exactly went wrong without even having her to tell you that in the first place. You score even more points because you took responsibility and didn't play the "blame game".