How do you get better in Tae Kwon Do fast?

The only answer is training. You should practice leg exersizes that specificaly target the ones needed for kicking, spar, build reflexes, practice kicking, anything that improves you for sparing. If its memorization, you should practice memorizing the techniques and hour a day. There are plenty of TKD vids on YouTube if you need a reference. The faster you need to get better, the more you should practice. But to much is not good.