I've been taking some shots of my new daughter recently. This one is a combination of natural light and an off camera strobe at camera left for fill:
Some key things to think about
:
1) Get the baby away from the background.
2) Use a fast aperture to blur the background.
3) I second what Lori stated about getting them close to your light source and using a reflector.
4) If you're going to add light, then you need to figure out how to balance the color of the natural and artificial light.
5) Diffuse! Otherwise it will look harsh. The more diffused and the closer the light source is to the subject, the smoother and softer the light will appear.
You can add light with off camera strobes, but if that's out of the question right now, consider using a
bank of daylight balanced fluorescents. Some people like the halogen work lights too.
Last of all, if the light sucks, move somewhere else. If your friend has tiny windows and you aren't comfortable with artificial, go outside. Shoot in open shade and use a reflector to fill in a bit. Works every time!
I did nothing in this picture except set her in the shade and shoot:
Good luck!