In the begining it's good to earn all the hero classic cards and get the feel for each hero. After that it's better to stick to one or two heroes at a time. Learn all the types of decks that works best for them by studying the decks already made. I hate to say it but netdecking is a great way to learn what top tier deck can do versus lower teirs. I still make my own decks and I still netdeck. (meaning copying decks from the pros who have thousands of games under there belt) once you get your bearings go crazy make your versions of the best decks out there or maybe even create something no one has ever seen before and destroy to legend! This still happens time to time. That's why I love card games like this, when your bored of something change it up, or make something new! The practice is always just keep playing. There's a lot of rng in hearthstone to the point that ANYONE can make it to the top. Don't get discouraged! Good luck!! Anymore more help feel free to ask!!