How to improve at soccer?

Hey! I have my school tryouts coming up in a little more then a month and I really want to make the team preferably jv1. (Levels are jv2 - jv1 - varsity) I am a defender but wants to do more and switch to a cdm preferably but I just don't think I'm good enough for jv1 yet. I've been practicing almost everyday but I go atleast 3 times a week to practice and been practicing stuff like shooting, and passing and improving my 1 star weak foot and juggling. I don't play for a team but rather play with my friends at the park who play for a high level team where I practice defense like once a week. I've been doing anything but practicing defense since I really don't know how to by my self. I really need some advice on what to do. Since I also want to switch to a cdm I've only been practicing, shooting and passing. Any advice on what to focus on to really make the team and improve as a player