Basically, the wet look is driven by the specular settings. The specular and specular colour settings control how much shine is shown; the specular nodes (glossy, anisotropic, and so on) control how the specular shine is calculated, and therefore it's final appearance on the model; and if you want a droplet feel to the wet look, then using one of the nodes such as spots or similar will break up the uniformity of the shine.

I'm loathe to give specifics, since every character and circumstance is diferent - there's no hard and fast rule as to what are the 'right' settings'. But those are the nodes you should play around with until you get the look you're wanting.

JonTheCelt