I use the wind. I've found that going to all the effort to cover, conceal, or control my scent, isn't worth it. I simply try and control the direction that my scent travels. I use the wind.
My experience is that they can smell me when I'm clean, covered, and concealed. Just a couple weeks ago, I was set up at sunset at the edge of some dark woods, and a bull elk came out to graze for the evening. He was too close for me to move at all, and he made his way to a spot that was directly down my wind stream. Once he hit my scent, he jumped and flailed about as if he'd peed on an electric fence. He then made his way out of the area, but not too quickly. The smell spooked him, but he didn't have any other sensory data (sight, hearing) associated with the smell, so he wasn't outrageously panicked. He was just uncomfortable.
But I've also stood directly upwind of an animal that was staring directly at me, not 40 feet away. I stood perfectly still, and he craned his neck from side to side, trying to get a look around me, to see what it was that he could smell. He then just slowly continued doing what he was doing. He wasn't really spooked at all.