I have been playing lacrosse for 2 years and am currently on a summer teamand I am also a middie.
1.Be aggressive and smart while playing defense as a middie so stay on your man or in your zone and watch out for illegal checks. Also if your going to hit somebody do it on their FRONT SIDE with your hands TOGETHER ( or it will be a cross check) and MAKE SURE THEY HAVE THE BALL!
2. On the face off get on the side of the midfield line that your defense is on and get behind the hash and when the ref blows the whistle run towards the people facing off to get the ball and if you face off get close to the ball with your stick parallel to the midfield line with both hands on the ground and when you hear the whistle put all of your weight on your stick forward and try to sweep the ball out.
3. Practice your dodges on offense and cradling, passing, and catching. Also be smart and shredding and also practice your shots.
Good luck!!

Alright, thanks a lot man. I have been working on catching, and using my left hand. But I'll work on this stuff too!
+rep for you;)