so sorry it didn't go so well for you today. But Brisa is one of the easiest to work with I've found. Try a set on a practice hand tonight. Really look over your shape you've created with the gel before curing. Then if you notice any dips/bumps ease the gel into place, then cure. You might have to do a bit more filing the shape until you get more confident in sculpting just with your brush. Until then, maybe add on more builder layer so that you can file the shape better without thining the gel too much. You want to be able to keep your strength and shape to make sure the set will last.
You could get models in to practice on and only charge 50% to cover your product costs and such? just a thought
Good luck and just keep practicing!