I have a tip on leaving a box.
This works out pretty well for me. Ex: If i have to move from a box to another box on the right, i will shoot right to left. I bend my right knee a little bit. The bending of my knee controls where my upper body transitons to.
This way i sort of get my momentum going to the right before i leave the box
If i have to shoot around a barracade i will shoot the oppiste of slicing the pie. That way my momentum is going to the right. (of course this only works for USPSA)
YMMV