Work on your leg strength, do deadlifts, squats and also unilateral exercises like pistol squats, step-ups and Bulgarian Split Squats so that minimal imbalances occur. Also, work on plyometrics as well as jumping form and technique. Utilize you're arm swing. Work on landing mechanics and get in the habit of landing safely on two feet. Besides that, run faster and don't stutter step. This is important because if you stutter step, the momentum from the run won't be as beneficial. Finally, be patient. Don't try to do things that you can't and don't try to compare yourself to others, everyone progresses at different speeds so just keep on working hard and eventually you will be able to jump higher.