Lighting:
X sets light source 1. You can go into the options menu(Num Pad *) to set the other two. The light source will be set wherever your camera is.
Set the light to a colour that makes sense for your surroundings(ie: white/or +1 blue for night. +1 red for sunny day. or try and match the colour of ambient lights from local light sources)
There are three different light strength options, but a lot of the time I just choose option 3 and set the light farther away from my subject.
Try and mix and match lights to both give ample lighting to your character, but also leave enough dramatic shading so as to not seem like they're standing in front of a spotlight.(Try a brighter light source from one direction and then a softer light source from the other, so there is noticeable shading, but not a stark black/white, unless that's what you want)