Just off the top of my head there are a couple of things to do – all of them within the camera.
Adjust your white balance to outdoors – Outdoor light tends to bluer while indoor lighting tends to go more towards the reds (especially with flourescents)
Change the ASA setting – if its bright, but overcast, go to 200 instead of 100
Fall back and use flash – Assuming that your camera has a macro lens, set it to macro (rose icon, usually) and zoom in until you've maxxed out the optical zoom (as opposed to the digital zoom which will give you poor quality images) There's usually a stop or line between the two. Now, step back until the figure is in focus. Set your flash to its lowest setting – even if you're outdoors. If the flash is still too powerful, but a piece of frosted adhesive tape across it as a diffuser.
Use white piece of paper as a background. If you're using a decent photo program, being able to adjust the entire photo until the background is close to pure white is a lot easier.
Bonus hint: If you've got Photoshop, or something that lets you work in other color modes, switch to CMYK. You'll be able to adjust the color a bit more finely. Be sure to return the color space back to RGB before saving as a .jpg.
Wyatt