Going small/light, or deep has never worked for me on really slow-bite days. Moving to different water (dirtier or clearer) usually helps, but if you can't do that then your pretty much stuck with what you have to work with.
Switching species can be a major savior. When the green/brown bass are in a major funk then the crappie, gills, cats, or white bass bite is often on fire. And vise versa. I can't tell you how many times I've beat my brains out all day bass fishing, then ran into someone at the ramp that had a stellar day catching crappie or whites all day. Fish species seem to take turns being the most active critter on a body of water during periods of time. Very seldom are they all biting good at the same time, so if targeting only one species all the time you are going to have periods where your catch rate goes down the tubes regardless of what you do.