I don't know that the nerves ever completely go away. You didn't stipulate which part of the docking
process gives you the most anxiety or whether it's the whole thing start to finish or whether getting into the slip is worse than coming out.
One idea is to load up on fenders and float your inflated dinghy
across the end of your slip (or run a line across the slip with a fender
floating in the middle). After that it's like learning
how to ride a bike with training wheels until you get more comfortable with it.
If that's not practical, then as others have suggested, find a buoy in the channel and practice approaching it from the same direction as your slip is oriented.
PS. How long did it take you to get comfortable parallel parking or merging onto a freeway when you got your driver's license
? Some things just take a lot of practice.