Let go of the person you like for a long time. The most important thing is not to contact him. Every time you contact him, you will be lucky. For you, this man's every move will attract your attention.
Time is actually the most powerful weapon and the most effective method. Delete his information, delete his contact information, don't follow his every move from social networks, don't sneak into his space to delete his visiting information, don't see if he chats with other girls, and don't see what he likes. Don't peek at his status from his friends.
I believe many people have done the above things. I know that controlling these things may not make you forget him, but it may make you more angry with her thoughts. Maybe you will hack his phone one night and log off the next day, trying your best to get his information back from others. Why care about a person who no longer loves you and misses you? You see, his life goes on. Why do you stop here?
Many people will say that as long as you treat this relationship rationally, it is easy to forget, and no one can do it easily.
I suggest you try to keep yourself busy, whether it's study or work, and set yourself a goal. When you are busy towards this goal, you have no free time. If you miss him, you will be so tired that you want to sleep as soon as you close your eyes every day. Over time, you will find that the person you love has only a vague image in your mind. Look around you more. Maybe someone is already watching you silently.