Teaching right and left

I'm looking for ideas about how to teach them to go right or left, moving away from me.
Dale follows hand signals very well so when we're out I just point and call 'this way' and off he goes. I don't think Chip has much idea so he follows Dale.
Obviously for agility I don't want him to turn and look at me so how do I do it? I've tried throwing treats and shouting right or left when he goes that way but it doesn't seem to be working. Also as soon as I speak Dale turns to look at me.

First I would get a good 'Go on' command (getitng the dog to go away from you....then move on to the directions.

I taught Laddie directions like this..
start with the dog in a sit or down a few yards in front of you. Place the ball a few yards away on the dog`s left or right then go back to your original place.
Call Left! (or right), flinging your arm out the same way the ball is. The dog dives for the ball, and starts to associate going that way with the word.
Do only one direction till the dog has got the idea.
When he has, place the ball in the other direction and repeat.

It works because getting the ball is the reward. I suppose you could use treats if your dog isn`t into toys.

eta - I taught sendaway as a separate excercise first- but it was a WT sendaway (to an unmarked spot), not an Obedience one (to a marker)

I'm using a sort of combination of the other's comments.

When on walks with a ball chucker, I will tell Stump to 'Go' - she starts running straight ahead of me. I then chuck the ball to her left or to her right and shout 'left' or 'right' as the ball is in the air.

She is getting there The only drawback with this method is at the moment she only associates me shouting left or right with the ball being thrown, so when it doesn't arrive she turns round to look at me in disgust

I taught both my girls the way Greg Derrett does by getting them to spin in each direction, originally luring, but then getting them to do it only on verbal command with them in all positions to me, both of them are really good at directions. Bertie just learnt by me saying the command as we turned as he doesn't run too far from me, he does know them as I have tested him.

I have taught kaos to spin and twist, but I think if I did it at a distance, he would just do the full circle and keep going the direction he was heading,

must give it a go though...

so if anyone spots a rottie running in a stright line, randomly spinning round like a mad dog...tis me lol

How did you manage to get them to go out in a nice right or left hand circle with it?

My girls have never spun on a course, they just turn to the jump and go over it, but if I ask them off the course they will spin.

Thanks for the ideas. Dale does send aways to a marker OK and I've tried just sending him ahead but he only goes a few feet and then circles me. I think he needs to build up confidence. In fact that's probably the trouble he keeps looking at me and I just don't run fast enough
I'll try spins and turns. He does them beside me so it should be possible to do at a distance.
I've been having him wait beside me and throwing treats to the left and saying the word when he goes for them so this will be something quite different.

Do you ever play the one Jump exercise?

What's that?

We've been working on turns so I've been practising a few jumps in different positions.