This is my personal work with the tee, it's what works for me but I guess I don't advocate it for everyone because I think people should do what works for them, just thought I'd share.
I mainly use the tee to loosen up...
I use it get loose and get to the point where I can backspin about 4-5 in a row to the back of the cage, then I move on to front toss. I usually don't swing too hard on the tee, just enough to feel out a good path to the ball.
Everything I hit off the tee is about belt high, down the middle or just on the outer third. I usually set the tee up in front of the plate and position myself so my stride foot comes down right in line with the tee. I try to hit everything on a backspin line drive up the middle. I like to set up the ball with the two parallel seams facing up/down back towards the plate(like this "||") and I think about hitting the inside seam to stay inside the baseball.
Every once in a while I'll do high tee to get the feel for some backspin. And if I'm struggling with getting out of the zone too quick, I'll set the tee up on the inner third and still work up the middle.
I HATE moving the tee to the corners. I feel like I can't get the feel for hitting the ball on the corners by hitting off the tee. I have no rhythm to my swing and I can never put the tee in the right contact point to where I actually hit a pitch on the inside or outside corners. It basically messes me up, so I don't do it.