One of the best tools to use in the studio is the Photovision Calibration Target. This simple item which resembles a photo bounce can be used to ensure your exposure is perfect and your white balance is correct. To do this you simply photograph the target filling you frame with equal amounts of the black, gray, and white bars. When you look at the histogram for this image you should see three distinct bars for each color. Adjusting you exposure to ensure the bars are not cropped on either the white or black side will mean your exposure is correct. Once you know you have the correct exposure you can set your camera to manual white balance and use the target to set again to set the white balance.
The following video from PhotoVision explains the process: