dalinise has a great tutorial for tears. I think it's on her artist page here, and there should be a copy on her website, too: www.dalinise.com For sweat the same principle applies, but you might also want to play with the highlights in poser: in the materials window the highlight colour for the skin is usually set to black. If you set it to white and play with the percentage on the highlight setting, you can get a nice "glow" effect, like the skin is shiny with sweat or oil. Then you can add beads of sweat in postwork to enhance the effect. Blood is a bit different. I've never tried it myself, but the most successful attempts I've seen have painted blood onto the texture map before rendering, rather than in postwork.