Actually i think relaxing as you learn the skill will help develop it more naturally. Before even starting any skill, stop, count to 5 or 10 (whatever you need), center yourself, visualize the next 5-10 moves, get stable, LOOK UP/HEAD UP! SLOW DOWN, relax, yes, breath normally, and commence with the skill... Did i mention slow down? Did i mention HEAD UP! Relaxing as much as anything will help you maintain trim and buoyancy. Getting all tense and stuff wreaks havoc on situation. If you practice the skill like theres a fire before you have the anagram in your memory banks, then you're going to perform it like theres a fire and likely miss steps and look sloppy.
I'm not saying go slow cause you can't reach things, i'm saying just make each movement very precise, very clean. flailing and struggling only destabilizes the system which adds to the task loading.
If you need to, practice the skill in steps. Thats where the Basic 5 comes from... break a valve drill down into right post, center, left post. get each segment wired, THEN put right post/center isolator together. once that is wired, put center isolator and left post together. Finally once all the steps are wired, and you are relaxed for each segment, put them together.
Do each skill this way, from fin kicks to ascent drills to failures. Stop, Breath, Think, Act (move)
Slow is Smooth, Smooth is Fast.