Well, I used it full strength (I.E., no thinning), picking up a generous amount on the brush. Applied it to the surface horizontally in about 6" wide sections, evening out the amount by going back-and-forth maybe a dozen times, then moved on to the next section lower, overlapping where I left off by ~2 inches.
NOTE: I used oil-based enamel, which has a longer drying time though, not sure if this technique would work as well for latex. I also let the first coat dry for 24 hours before applying the 2nd coat.