It is tempting to load up the brush so you can finish faster. Thick coats cure unevenly, wrinkle, and peel off in sheets because the top has cured while the bottom is still wet.
Two or three thin coats will always outlast one heavy coat. Wipe the excess off the brush on the bottle neck before it goes near the nail.
How many coats of gel polish do you usually need to get full coverage, and which polish or gel do you find is the worst offender for streaking?