Tripod, tripod, tripod!
After that, the best way would be to shoot either full manual or aperture priority. The larger the aperture number the better depth of field you get so for those side profiles you will get the front and back of the case in focus. Better lighting could help, but it's mostly more about the stable platform for the camera. Also, for longer exposure times, it usually helps to use the timer or remote to trigger the shutter as just the action of using your hand to press the shutter can cause the smallest movement which will then mean fuzzy focus.
What lens are you using now? Is it the kit lens (18-55mm)?
Oh one other thing - the white balance settings are somewhat important as well. Check out this post I did on white balance settings and differences