Walk - well.. not sure. Just asking him tro go :P
Flatwalk: Squeese gently with left leg/ankle when the left shoulder is moving backwards, and right leg when the right shoulder's moving. Stops when he has the speed and gait I want.
Rack/saddle rack/slow gait: Squeese with both legs at the same time. Sits back a bit.
Trot: taps with one heel gently. This comes from when I started to trot him I had to bend him a lot and kick/tap with the inside leg to get a trot. Now that tap is the trot cue.
Canter: I start canter from a racking type gait. I simply move as if he's already cantering, he picks up the move. If he starts rushing I take him back and try again.
That's my cues. :)