please wear your jacket through out your warm up. getting your core temp up is going to be much easier if you leave your Hoodie and sleeves on.
but anyways, get a few poles in to loosen up, then I like to go run about 6 90 yard sprints followed by agility ladders. I'll go through a dynamic warm up and get the trainer to stretch out my arm, shoulders and back and align my hips and upper body.( sometimes alignment gets a touch out of whack in high school because of growth spurts and such, or at least for me.) then i like to loosen up with some light weighted ball tossing against a wall and run over some drills to feel out my mechanics then I get going. during the game, doing jbands can help keep your cuffs warm.