Most people (fishing any tackle) underestimate the power of a slow retrieve coupled with a fly/lure that has a ton of movement even when it's sitting still. I often have bass hit flies when they've been sitting motionless for minutes at a time or during long pauses between strips. This is especially important when fishing heavy cover as the bass needs time to leave his ambush point, find the fly, identify it as potential food, then eat the sucker. The bigger/smarter the bass, the longer this process will probably take. Lately I've been fishing flies with a lot of rabbit fur, marabou, rubber legs, or any other material that with move a bunch even when I'm not manipulating the fly. If the book you read was Terry and Roxanne Wilson's, I found it to be very helpful, myself, but there are always things peculiar to the particular water you fish that you'll have to puzzle out on you own.
One other note: Many of my largest bass have come on flies much smaller than you might associate with bass fishing. Big flies weed out the little bass, but even big bass will take small flies if they fit the forage profile of the water you are fishing.
If it swims and eats, it'll eat a fly.