Check out
The Retriever Journal for recommendations on DVD that will help you with your training.
We have a Lab as well and she has a high retrieve drive so we just played fetch with her like crazy. Hubby took her duck hunting for the first time last week and she didnt need much motivation to get her going.
We started training her to simply fetch, by throwing her a ball (or whatever) and then calling her name so that after her retrieve she would come right back to us. Secondly, we taugher her "Drop it" so that she would drop her ball/bird on the ground and eventually worked it so she drops it in our hands. Thirdly, we'd tell her to stay, throw the ball, wait a few seconds, then tell her to "go get it" and send her after the ball. The dog needs to learn patience when on a retrieve so please teach her to stay as soon as you can.
Those are the steps we took with our dog and she's showing promise. Make it a game for you pup and you'll tap into their instincts soon enough.
Getting a dog to be 100% obedient will take lots of time and practice, and lots of patients on your part. The only worry I have is that if you focus too much on the obedience, you may 'break' the dog and that will take more time to fix and get their confidence back up.
And one more thing, practice blind fetches....throw the ball behind something, get the dog to take its eyes off of where it landed, wait a few seconds/minutes, then send him on his way. This builds their memory. But start easy to build their confidence up. If you see the dog struggling, go back to an easier blind retrieve and go from there....
Good luck!!!