With black tattoos, try creating two layers - on the lower one, add a slight gaussian blur and set the mode to colour burn and on the upper layer add a sharpen filter. Play with the opacity on the burn layer (I find around 45% works well). For coloured tattoos, try a slight drop shadow. It sounds nuts, but it does work. Alternatively, another two-layer technique: set the lower layer opacity to around 75%, normal mode, and the upper layer to 'colour' mode. Play with the opacity and see what effect you get. This works with some colours, but not all. Wounds and scars need a bump map to look right in Poser. There are a few different tutorials out there, but for a simple bump map just greyscale the texture and add some contrast. If you're using Poser 5, you'll want to set the bump strength quite low (P5 is way too 'enthusiastic' about bumps).