Bottom line on this is that there are two reasons a retriever will make a retrieve:
1) He/She WANTS to
2) He/She has been trained to
#2 requires the force fetch and Mike is right, you shouldn't be doing it yet. So all those books will tell you how to make #1 happen. The majority of it is in your hands, you can help build the desire for the dog to want to retrieve ANYTHING that drops from the sky. You have to keep at it for an extended period of time and have an absolute boat-load of patience. You have to be creative, enthusiastic, understanding, demanding, and PATIENT. Make your goal this off-season to learn as much as you can about training, and to take that knowledge and devise a plan to progress your dog.
Some dogs do it out of the box, others don't.... I know this doesn't really help you in the short term but you seem intent on learning. Consume the info in the books you have and set your mind to doing it. That is 75% of the battle.
"I'll start spending less time with my dog and more with my wife when she starts fetching ducks for me"