I'm no dressage rider, so my cues are very sophisticated.
My horse also has two middle gaits, so everything's a little strange.
Walk: Click and apply light calf pressure. Yep.
Trot: Lighten your seat and close your hip angle. Ask for forward motion with a strong click. Post. Keep reins looser than usual and hands low, asking horse to drop her head. Nudge a little more to ask horse to raise her belly, round her back, and pick up a little more speed. After a couple strides, you should have a fast trot. Slow your post and ask her to slow to a working trot.
Gait: Sit DEEP, open hip angle. Move toes a little in front of knee. Ask for forward motion with a light squeeze of the calf; the transition can't be too quick. Pick up contact with reins and ask horse to both raise her head and tuck her nose slightly. Sit BACK, chest back.
Canter: Pick up inside rein and nudge with outside leg. Works from a trot, gait, or walk. Sit BACK, or else you get a gallop.
Gallop: Go into a half seat. That is all.