Practice often. To really get good at this game you should be practicing every day. Even if it's only a little bit each day, it makes a big difference. Movement is typically the focus of said practice for me. That and perfect shielding (I make a tag where every button is special so that I can mash buttons with my wrist on a second controller while I attempt to perfect shield reflect).
That said, you should b reverse your quick draw more often than doing wavedash -> quick draw. Wavedash -> quick draw gives your opponents earlier ques to help them predict you as it has start up (jump squat + 1 frame of air time) and end lag (air dodge landing lag, which is 10 frames). Since you have a ton of options out of wavedash, it's still pretty good, so I'm not saying don't do it at all. Just that b reversing quick draw is often the better choice for quick drawing towards the opponent (say right) while you are running or dashing away (running/dashing left).
To do this, hit side b in the direction you are dashing/running (in this example left), then immediately flick your joystick in the opposite direction to turn it around (so flick the stick right in this example).