Hey, as a utility back with a preference for scrum half I may be of help. the main thing you want to practice is passing to both your right and your left as you have to be able to do each. Try and make sure you don't have to take a step away from the breakdown to pass as opposition forwards will try and smash you disrupting your distribution.
Make sure your fitness and pace are good as you have to be quick getting to every breakdown. You can practice your kicking as well but really unless you really have to you should have your fly half kicking.
My other tips are get to know your forwards well and you must boss them about and make decisions. If they don't listen you can't work anywhere near as well with the rest of the team. Listen to your flyhalf, he will say if he wants the ball. These calls change at every club.
My only other piece of advise is if your first to the breakdown and quick ball isn't an option, ruck over, don't wait for the pack and allow the other team a turnover.
Its a fun position and once you get used to it you'll be able to read the game and when is best to make little breaks from the back of a ruck.