Okay, here goes.
First, get a simple backdrop of non-reflective cloth, a dark color is best. Set up a couple adjustable desk lamps on either side to reduce shadows. If the light looks too harsh, drape a clean white handkerchief over the light source.
Next, get out the manual and find your adjustment for white balance. Get it set to incandescent light. Your setting is for daylight and regular bulbs give a yellow/orange glow in this setting.
Next, look up how to get the camera to do spot metering. This will tell the camera to read light only a very small portion of what's in the center of the viewfinder.
Now, find how to get macro set up. This allows the camera to do tight close ups. If you can, chose an aperture priority and close it down as far as it will go. You'll need a tripod, since your exposure wime will increase.
If you don't have macro and can't set the white balance, your other option is to move back from the model and use the zoom feature coupled with the flash.