How to Forget About Someone Important

1.  Give yourself time. It's a terrible thing to go through a rough breakup. It would be nice if there was some way to force yourself to pick up and move on at the drop of a hat, but that's just not how people work. Like it or not, you're going to need time to heal. This guide can only help guide the healing and hasten it somewhat. It can't reduce the time you'll need beyond a certain amount.
2. Use your personal space. Maybe you own a home; maybe you only have half a bedroom to call your own. Whatever the case, find times and places where you can be alone with your thoughts, and let them come naturally. When you have personal space, you have no restrictions on your thoughts. Knowing you have a place where you can be totally honest with yourself will help you cope with your anger and sadness in other areas of your life.
3. Remove all reminders of this person. Purge your life of anything that brings up painful memories of this person. Not looking at these things every day will help you move on.
4. 
   Resist the temptation to call. Especially after longer-term relationships, the urge to get back in touch with your ex can be overwhelming. Do your very best to resist it; it will only make things worse in the long run.
5. Cut off contact. You can't forget someone if you still see him or her all the time, or constantly hear about his or her activities
6. Talk about it with the opposite gender. Sometimes that can make things easier.
7. If you are in school and have a class with them, ignore them and hang out with your own friends. DO NOT TRY TO MAKE THEM JEALOUS. It will just create a cycle of you two attempting to make each other jealous.
8. Stop thinking about him or her. Once you've cut off contact and removed visible reminders of this person, it should be easier to avoid thinking about your pain. If, however, a sudden thought does intrude, stop it in its tracks. Say "no" to yourself or out loud, and immediately shift your attention to whatever is in front of you. Resist the urge to wallow in self-pity, and resolve that thinking of him or her in any way is off-limits.