Whenever I throw, the yoyo always seems to tilt. how do i work on my throw?

Practice. Unless your string tension is bad, the only thing you can do is practice. You can practice with an imperial-shaped yoyo, those need a perfect throw to work.

another way is to go up to a wall and throw flat against it (if your throwing a breakaway). Another way is to do it repetitivly. Get a responsive and just throw up and down for a while.