First off, if you want something with a little drama, change the lights from infinite to spots, then work with the dials to properly position the lights on the figure. Three spots will give you what you need, more often than not: a main light, and two side lights in contrasting colours. So you don't overbleed the image with light, experiment with shading the main light down to about 80% of value, then work with your secondary lights in dark but strong colours -- you'll get a really nice balance that way. If you're looking for a chairoscuro look, move your secondary lights to the same side of the figure and shift the position on your main light to favour them as well, leaving one side of your figure in black. The best tutorial for lighting? Get a book on theatrical lighting. You'll find theories on colour arrangement and how to use it to create an emotional response, as well as how to arrange your lights for maximum impact.