Everyone who says "You get better just from playing" are not quite right. You won't get better unless you make an effort to. If you have a hard time landing combos/hitconfirms -- it doesn't just magically go away. You need to be actively thinking about your match - how you're going to land your next hit, and how you're going to confirm that hit in to a combo. After a while that will become second nature, but at first you'll do a lot worse.
Anyways nothing feels worse than wanting to get better and not being sure how to improve - so I've been working on a "how to practice" tutorial. Keep in mind of course that you're playing a game against other people, and they can improve too!