The nail polish will sort of settle into place in an even way. You don't need to carefully brush it on until it's even. I usually just do one stroke down the middle and then one on either side, and then it will sort of level out on its own. Depending on the polish and brush, one down the middle might be sufficient.

Kinda hard to describe, but once you get a feel for it, the whole process is way faster and easier.

Be sure to experiment with having more/less in the bush, and pay attention to whether it was too little or too much.