In the end, you need time and stuff, I played like 120 matches just today cause I was in a roll lol. This is how you get better, you just grind it out. :D
I finally fought a good Millia...and oh boy is she trouble with those oki setups and instant overheads. I won maybe a third of the matches but it was all entirely fun. Played the same random person for like 3 hours lol.