The most difficult thing to do in a relationship is to hold up a broken one. Adjusting to a new status and life, and trying to forget things, events and times you must remember first to forget, is difficult at best. The prospect of being alone in the world is a daunting one, and many people who just underwent a break up succumb to the fear, and either hastily form new relationships or attempt very much â€“sometimes pityingly--- to recover the old one. Some succeed, but many fail, and in such ignominy it scarred them emotionally for life.
There is no secret formula for trying to make-up with an ex that might be effective in all cases, but there are several measures one can do to mitigate the effects on one's self, as well as start the campaign to win him back. The measures are of course also not foolproof because individual cases require varied actions ---different strokes for different folks, as the truism goes--- and often contrary to the common responses to a break up, but they have proven effective in many instances. That being said, it is up to you to adopt them. The measures are essentially:
Keep your dignity. A wise marriage counselor once said the greatest single factor that breaks up a marriage or relationship is the contempt of one partner for the other. They may look loving and close and happy together, may even manifest the signs of true love of each other, but if there is contempt in any one, the relationship will not last.
Thus the most pathetic act you could do is to call on your ex and beg him to reconsider you. Calling him, begging him, or even threatening him will do nothing ---and in fact do the opposite- to encourage him to take you back. Abasing yourself is the not the way to go. The best you can hope for will be for him to have pity on you, so no matter how well the relationship will look, that pity will stay, and the relationship will be flawed at best.
Accept the break up. While reminiscing on the past happy moments may remind you of your relationship, it may make you pine for them and do the above. Accepting that those moments are now simply memories will enable you to begin anew like opening a new chapter in your life. You will adjust easier to begin the reconquest later.
Assume a new personality. Analyze yourself and see what things he disliked in you. Were you too impulsive? Learn self-control. Do you dress sloppily? Study fashion and how to look sophisticated. Assume the person your ex wanted you to be, but assume it wholly, not just as veneer. In this way you will present to him a new picture that he will like.
The objective actually is for him to want you back, and not you wanting him again at least superficially. And the best way is to let him see you can survive without him, but can he survive without you?