It does take many hours of practice. I didn't feel my FMQ was very good, either. And I wasn't able to spend the time needed to improve it quickly enough. That's one of the reasons for my Qbot purchase. But there are designs, which are easier to learn. Loops are one of them. I've gotten to the point, I can do loops fairly consistently and can manage a spiral or two. I still don't have the knack of feathers or any of the more complicated designs. I leave those to Qbot for now.
Some LAQers practice designs by repeatedly drawing them on a dry erase board. This helps get the motion of the design into your brain. The movement of your writing hand mimics the movement of your hand while guiding the LA.
Keep with it, you will improve. And before long, you'll be an expert. And knowing you're a perfectionist, it's probably not as bad as you're making it out to be. And even if it is, your granddaughter will still love it.