Those are the two things I concentrate on when I begin my search. The season will determine where I start, but during the search, I'll try different speeds while attempting to maintain a certain depth. Sometimes that involves changing lures. For bottom, or topwater it's a little easier as lure choice will help maintain the desired depth. Then it's just a matter of finding the right speed, or interruption of speed, that will trigger a strike.
I don't experiment much with color, even after I find the depth and speed. If activity slows, I'll search for other areas that offer the same criteria the one I'm on has rather than try to milk a couple of extra fish off the spot. Keep in mind that if you don't have mobility, changing color, or even brands of the same style lure can increase your catch rate, but if numbers are what you're after and you have that option, move. To me, that's what pattern fishing is all about.
As far a Buck not making mention of changing or bad weather conditions, "moods" of the fish, size, color, action, oxygen, pH, odor, casting ability, traffic, rigs, "method," "technique," or "patterns: He is refering to catching more and bigger fish, not finding them. Most pros echo him when they say that after catching a fish you'll need to replicate what you were doing if you intend to catch another. If you aren't concentratiing on depth and speed, you'll never be able to do that. That's why whether I'm still searching, or I've caught a fish, this two parts of the equation are most important to me.