Here is how I dried brushed,
My first coat was white primer. I did a very light coat with the grain of the wood.
I then took my top coat of latex paint and with a tiny bit of paint on the brush, and I mean tiny, I brushed with the grain, while the paint was still workable I went back over it against the grain to cover up my brush marks. As you can see it gets rid of any harsh lines but still allows the white to show through.
When I first attempted dry brushing I was worried it was going to be very time consuming but I found it to be the opposite. Since you are applying such a small amount of paint you have less runs!!