I came from a Sea Ray I/O also. The tip that has helped me the most is to bump the throttle as often as you need to. Go into gear for a split second to get you going in the right direction, and then into neutral. Once you start going offline again, bump it into gear, and then into neutral. I'll do this pretty much every 2-3 seconds when docking, especially if it's windy.

I'm not sure I'll ever get used to basically having no control in reverse, but knowing what the boat will do is 90% of the battle.