Use a small, soft object that's easy for the puppy to carry such as a rubber ball, a knotted sock, a pigeon wing, or a puppy-sized bumper. Show it to the puppy and move it in a wiggling motion that will entice her by awakening her chase instinct. A short length of rope attached to the grommet on the end will enable you to throw the bumper with more distance and accuracy. As your puppy's abilities increase you can increase the distance she is retrieving and the amount of cover she is working in. Praise and confidence are key words.
Nothing succeeds like success.
Your local Golden Retriever club should be able to advise you on this. Unfortunately, not all Goldens are Retrievers. The dog may simply lose interest in retrieving, or develop the bad habits of grabbing, biting or refusing to let go of an object. M ake the introduction to water as pleasant and as enjoyable as possible. A warm day and a clean pond or a quiet stream with a firm bottom no deeper than the puppy's elbows is perfect.