Based on my observations:
1. Playing the match from the wrong distances (particularly up close).
2. Walking forwards or backwards to navigate space (kills charge).
3. Throwing random moves with heavy risk and poor success rates (e.g., EX Sobat).
4. Wasting meter on poor options (e.g., EX Air Slasher in fireball wars).
5. Not saving meter for MUCH better long-term options.
6. Hitting too many goddamn buttons (in the hopes that something connects).
7. Either not being aware - or not making use of - Dee Jay's MANY heavy damage options.
If you figure out ways to eliminate the above habits and replace them with better options, you'll automatically better your game by a shitload. NOTE: Will present a few ways to do this in other posts.