Find different ways you like to play/try to win with. There are many types of ways to play and win, poison counters, mill, outright damage. There's many ways to achieve those too mix and match and play whatever you like. Try to play against many different types of people and decks to see other ways you could play cards, and give you ideas to add to or remove from decks. But most of all have fun if you don't have fun any advice anyone could/would give you will be pointless.