I remember watching this guy about 5 years ago, who paints boats professionally. He was doing a little moonlighting outdoors. He was really old school not even interested in rolling and tipping, just a brush. And you can see he's finishing horizontally and was really brushing it out as opposed to "tipping".
Well I had to get within a few inches to find a brush mark. And you can see no special concoction was used, just paint thinner and oil enamel. But the mix of the two was pure experience. He just knew what he needed for the conditions. His staging makes it pretty easy for him to move. He did this 35'er in about 3 or 4 hours.
Every time I paint I get better. Still, especially outside, painting is tricky I find.
I'm with you Al, I think I could learn a lot more and faster if I worked with some of these folks that do it for a living.