I think that enthusiasm is the cornerstone of good cock sucking, but its hard to teach that.
Sir keeps me motivated by making sure that the only pleasurable thing happening to me is having a mouthful of cock. That seems to work really well. :)
Also helpful to lay out some specific rules and things to think about while sucking (these are Sir’s rules for me):
-Depth: consistently going down far enough to please my cock as much as possible
-Tongue: proper use of tongue while sucking
-Enthusiasm: showing obvious desire / motivation to please and suck like it is your favorite candy
-Moaning: making sure to give grateful moans while sucking
Other than that- practice a lot. The mirror dildo has been very helpful for me and Sir likes making sure I have to watch myself acting so slutty.
Thank you for the question. :)