@pacoparrot:
…..he will only sit or lay down if I have a treat to lure him into position. He's also making progress with bringing his toy back instead of running away with it and leaving it somewhere. I haven't been using my clicker but I think I will start!
Yes, you can fix all this with the clicker. I am not a fan of luring, as you can get "stuck" with the dog expecting a bribe and not bothering to do the behaviour otherwise. You want to fade the lure as quickly as possible, possibly using your empty hand as a bridge, but really, sometimes lures get in the way of the animal actually understanding what you are requesting. Clicker training make things much more clear to the dog, IMO. If you haven't used a clicker, or have any questions as to how to proceed, there is a lot of information on line. This link has an interesting article on teaching sit and down with a lure, and how and why to fade the lure:
http://www.clickerlessons.com/sitdownstand.htm
I actually prefer to "capture" the behaviour, rather than luring it, and since you have been luring it might be good to change your approach. More information here:
http://www.clickertraining.com/node/598
As far as retrieving, I prefer to start by teaching "pick it up", so that my dog understands that means pick up whatever object is indicated. You can proceed from that to naming the objects, and eventually to having him bring you the thing you request.