I've never been a serious player, but I originally learned how to play with one of the Let's Play! discs back in the day. These days, with up-to-date mechanics and more in-depth tutorials, Pokémon TCG Online is the way to go. If you have any questions about specific cards, feel free to post them here!
EDIT: Whenever you're ready to start playing physically, consider investing in sleeves and a deck box to minimize wear to your cards.