Watch Step by Step Instructions over and over on how to shape, then back chain together all the behaviors needed to have a solid retrieve to hand for bird dogs and gun dogs. All positive.
Tips for training given as you work through the process. Practice each step until your dog can do it correctly 8 out of 10 times in a row. When you add the next criteria, your dog should be successful 50% of the time. If she's not, you need to simplify something for her so she can be.
You can use tugging to increase desire for the bumper between sessions if you use a different toy, not the bumper.
This method works for natural retrieving breeds as well as non-natural retrievers such as Jessie. It allows you to retrain any part of the retrieve chain that your dog is not proficient with.