Guys, don't blame your hand unless you have a condition that makes it difficult/impossible to move your hand in a precise fashion. The problem is your brain.
The 'crystal clear' imagery in your head is not actually crystal clear. The clarity is only perceived, felt, but is not real. If you could really see it in your mind as clearly as you can see an actual picture, you should be able to trace your own imagination on a blank sheet of paper. BUT YOU CAN'T!
Anyone can get a "clear" vision of, say, a cute rabbit rolling in the grass. But just because you can "see" it in your mind, doesn't mean you actually know what a rabbit even looks like. I don't, even though I physically see those fluffballs in my yard every night in warmer months. Long ears and fluffy tail, sure, but head structure? Body proportions? Nope! The clarity is not real.