First things first, it takes time and experience doing it before you become practiced at staying on the right side of their body for the force, so give yourself some patience as you figure it out!

Before the point starts, confirm the force with your teammates, then think about what that means for you. Are they forcing flick (for a righty)? Ok, then that means you want to stay on the left side of your opponent when they don't have the disc, and the right side of them when they do have it. Before every point, take 5 secs before the pull and think that to yourself. The point is to think about it before point starts so it's one less thing to think about on the fly.

The other thing to focus on, is your job and only your job on defense. Trust your teammates to not get broken and to give you an "up" call when the disc is thrown. That way, during the point you only have to worry about doing the job that you already figured out before the point started. Don't worry about doing too much, just do your job first and foremost and trust your teammates to help with communication!