Keep it fun and use several short workouts compared to one or two long ones. Repitition is the key, but long workouts cause a pup/dog to become bored which can -- and usually does -- lead to problems. Try working the dog indoors in a hallway -- so you have total control over him -- for about fifteen minutes, using one to two hour intervals. I've never had to use force-fetch, but many post that will follow will probably suggest just that.