do it in a alleyway or hallway indoors,then its got no where to run off to,lots of encouragement,dont bore the shit out of it though,little at a time,cuddly toy or socks usually do the trick,even get a rabbit skin and make a dummey
bang on!that's how Ive always done it.1 thing I'll add,its got to be a game for the pup,dont gget carried away with early success when the pup starts lossing intrest in the session stop aand move the dummy out of sight and do it all again later.when you get a good retriving dog dont be tempted to drop the catches for your mate's pups to bring em on that spoiled