Try to understand what caused the breakup. Do not engage in self-abasement and at the same time, don't blame just your ex-girlfriend. You just have to calmly think things through and understand where you went wrong. Bitter experience will help you build a more successful relationship in the future and not to step on the same rake again.
Do not neglect communication with other people, including women. Withdraw into yourself and choosing isolation and voluntary seclusion, you only worsen the situation. No need to compare each familiar with his ex-girlfriend to try to consider women features lost sweetheart. Just communicate, go out with friends to a movie, leave town, have fun.
Understand that you broke up with your girlfriend completely. Often people torture themselves with the hope for a return of love, the magical restoration of relations. Get rid of illusions. It will hurt, but if this is not done, the pain will be more terrible and prolonged, and eventually you just get used to live with her and give up.
Change your life. Stop to visit places that cause Association with a former girlfriend, get rid of the love gifts and photos. In some cases it is even appropriate to make the repairs, or at least to change a little interior of the apartment: to acquire new textiles and decor, rearrange furniture, etc. Your house doesn't have every second to remind you of the happy hours spent with a former girlfriend.
Stop idealizing the past. Looking back, people often tend to see lost love only pleasant, especially if the breakup was painful. This becomes even worse: the man reproaches himself that lost such a beautiful, smart, beloved, the best woman in the world. But it's a lie. Remember quarrel, unpleasant situation, resentment. Relive them again, remind yourself how much pain you've caused you ex-girlfriend. So it will be easier to forget her.