Mainly what everyone else has suggested.
Practice, practice practice.
Any time you are not using the longarm, and can, practice drawing even if in the dust on the furniture! lol
I draw on paper, on table tops, anywhere just got get the feel for a pattern.
And yes, remember to breath and relax. Keep your grip relaxed otherwise your muscles will hurt.
Go with the flow of your body not just your arms.
Post your progress!
Have FUN!