Any person has his own shortcomings, but there are much more advantages in him. He just does not see them in himself, but at the same time he gets hung up on negative aspects. This is often the main cause of the complexes.
"Appearance is not the main thing" - the truth for centuries. There are many examples when famous people had the most outstanding and sometimes ugly appearance, but this did not prevent them from gaining worldwide fame and love. Probably, they got all this not because of their external data.
Dig into yourself. What distinguishes you from the gray mass of people around you? What makes you an interesting and extraordinary person? Emphasize this. But don't stop there.
Change yourself for the better - this method is straightforward in dealing with complexes, but at the same time it is quite effective. If you still don't like your appearance - change it! And more activity.
Learn to love yourself for who you are. But also do not let strangers offend you or mock you. Protect yourself with your wisdom, not your strength. Joke - humor kills aggression in the bud.
Open yourself to the world and the world will begin to love you. Be strong, the world loves strong people.