I have suffer long from acne since teenage time. Apart from taking medical treatments, what can I do to have better skin?

Diet, vitamin. You can see some improvement by avoiding sugar, regular mik and grain based simple carbs. Naturally clear is an oral and topical vitamin supplement we have used with success that contains zone and topical niacinamide.
Better soap... The best thing to do is use the best soaps/facial regimen you can find. I would try an oatmeal based soap; followed with a tea-tree oil based skin cleanser. {i would really like you to see a dermatologist as most severe acne can be simply treated; but that is up to you}.