How do I stop thinking about him?

Try to focus on your hobbies and on your friends, try to distract yourself. Sometimes, going out with friends it's the best way of stop thinking

Let yourself think about him. Suppressing feelings can bring them back stronger, however if you're uncomfortable with this, try finding someone new to focus your attention on.

This is going to sound very harsh. Delete his contact, delete him from social media, avoid seeing him as much as possible, and get rid of all the reminders that you can get rid of. Even if only for a few weeks, it'll make him less significant in your daily life. Also, Maybe focusing on other relationships and friendships might help! During this time surround yourself with other people and try to be as less alone as possible. Also focus on developing yourself. You want to learn the guitar? Get back on track with sports? Go do it! :)

I try to busy myself to keep him out of my mind. Tv, reading, writing, or physical exertion that requires all of your attention on him

Delete everything that reminds you of him & keep busy! Surround yourself with the other people in your life that you love and think positively about yourself.

There are many ways to take your mind off of a previous relationship. The most important thing in this situation though, is self-care. You could take a walk outside, read a book, journal, talk and hang out with some friends, or do anything in general that makes you happy. He'll always be there, in the back of your head, but you must persevere and continue on. Preoccupy yourself and be sure to constantly remind yourself of your relevance. You're better now, so let it stay that way. Always keep yourself in your best interests.

I think the best way to allow yourself to stop thinking about 'him' is by finding new hobbies to do or bouncing back into some old hobbies that you might have put off for a while! Take some time to take care of yourself and give yourself time to not think about him. Make sure to not linger on past conversations/pictures or anything else that reminds you of this person. This definitely may not be an easy task to accomplish but with time you will come to see that you have so many things in your life to be happy about and think about that you won't have time to think about him! Stay strong!