Summarize the following:
Break-ups can hurt, and seeing your former boyfriend with a new rebound relationship can feel awful. However, you need to allow time for dust to settle on your old relationship before you begin planning how to get your ex back. A couple months is ideal, and a month is the absolute minimum you should wait before trying to get him back. You risk appearing desperate or clingy if you rush into your attempt to win him back. This gives him ammunition to use against you to paint you as the crazy ex-girlfriend. Resist the urge to immediately start trying to win him back. Where did your last relationship go wrong? Did he cheat on you? Did you leave him and now regret it? Did you guys have trust issues? Think back to your relationship's biggest problems and think seriously about how you will address those going forward. You don't want to win him back only to immediately lose him because nothing has changed in your attitudes and expectations. It can be easy to feel bitter and resentful after a break-up. When you've put a lot of time and energy into a relationship, it can be hard to see your ex happily moving on with another girl. No one wants to take back an angry, bitter ex, so you need to direct your anger into something positive. Some good ways to redirect your anger are taking high intensity classes like kickboxing, so you can physically release your anger, or you can try journaling or meditation to work on channeling your anger into something positive.

Summary:
Give yourself some time. Assess what went wrong the last time. Redirect your anger into something positive.