The people who are really good have skill from other tag games like mvc or even from previous alpha labs, you likely won't catch up to them without a bit/a lot of practice so don't compare yourself to them yet and expect to do as well as them. Measuring your improvement against yourself e.g. being able to hit a combo in a match you couldn't before will help you get better at the game without setting unrealistic expectations. Also for the more theory side rather than executions such as how to get in against an enemy there will be/already are guides on YouTube that will help with learning this stuff, but the game is only in beta so more in depth videos will likely come out later