How to get better at high jump?

OK so the very first time i tried high jump i started on a low height then like right after i passed those i tried 4 feet 6 and it was a cold day and foggy and i was waring converse and i slipt. How do i get btter thats all ive done in high jump but if i could i would practice 24 7|||I think you should have a coach to guide you properly.