Okay, Robin Sallie, you've totally inspired me to write about what I know of Gundog training, so here it is!
First of all, if you want to know more, here's two great books on the subject:
Positive Gun Dogs
Secondly, 'normal' people think you're weird for doing gundog training with a Shepherd, but if you both enjoy it, why the hell not?! ;-)
I spend most of the time doing retrieves, and there's three types of retrieves:
a mark/memory is when the dog has seen the exact location of where a dummy lands after it is being thrown. Officially, the dog should find this dummy on memory and sight alone, and she should not start searching - using her nose - to find the dummy once she's in the general location. Memory comes into play when the dog is not allowed to retrieve immediately after the dummy lands, but has to remember where it is in order to retrieve it later.
a blind is when the handler and the dog have a vague idea of where the dummy has landed, and the aim is for the dog to go to the suspected dropzone, and then use her nose to find the dummy.
a directed retrieve, or casting, is when the handler knows where the dummy has landed and the dog does not. The handler then uses hand signals to direct the dog to the dropzone, and the dog then finds the dummy through nosework.
For the dog, there's basically only two kinds of retrieves; a mark/memory, or a blind. Choices are either to find it with your eyes, or to find it with your nose.
An example of a good memory is the first retrieve Luna did on Jan. 29; I tossed the dummy, she watched it land (this is the 'mark'), then I took her 186 yards away -I decide on the distance by looking at Luna and keeping in mind dog and human traffic, as long as I can tell that she knows there's a dummy back there, I can keep walking. If she looks even mildly like she's forgotten about the whole thing, I do not send her or I walk back to where I see her remembering the dummy -. Then, I turned to face the direction of the dummy, and I asked her to retrieve. Sometimes I have her Sit, sometimes not. Luna took off, and came running back immediately upon hitting the dummy. I could see where the dummy was, and she very clearly ran right to it, picked it up and came back. In other words, she did not have to search for the dummy, she knew exactly where it was. This is what a good mark/memory should look like.
A word on the color of dummies; there's green, brown, orange, white, and black-and-white dummies available. Dogs can't see green, brown or orange very well, in fact, on our last Gundog training week, my orange dummies eluded several dogs; they ran right past them, went 'huh?!' and then found it by nose. I use the orange dummies specifically so that I can see them, so that I can find them when Luna can't. If you want to make sure your dog can see the dummy well, use white or black-and-white dummies, or simply put a white sock over the dummy.
I've also numbered my dummies. I've done this so that I can find out which pattern Luna has used to find several dummies. Does she go deep, does she go wide, does she have a tendency to go right and not go left, etc. Something Luna finds hard it to go into the wind; her initial reaction is to go with the wind. But if the dummies are into the wind, then how is she going to find them?
Another tip when starting out is to use lines in the landscape to help the dog. I do most of our retrieves at this point on roads, dirt tracks, between tree lines etc. Doing retrieves on a piece of land with no lines is quite hard for new dogs. Also, try to use lots of different terrain to teach the dog not to be bothered by boundaries; from grass to dirt, from grass to tarmac to grass, across water, over fences, etc. You'd be amazed how many dogs think that going from grass to dirt couldn't possibly mean that the dummy is in the dirt, and not on the grass! Luna showed another example of this on Jan 29, when I had tossed two dummies between trees. For a while she kept going back and forth in front of the trees before she decided that no, they really had to be behind the trees!
So, this is a little bit of what I know about Gundog training, specifically the retrieves. If anyone has more questions or wants clarification, don't hesitate to ask!