Is there anything I can do to prepare my car for the smog check? I want to make sure it passes. Thanks.

Make sure all emmissions devices that are applicable to your year are present and functional. A properly maintained ignition system always helps, good plugs, wires, cap, rotor, proper ignition timing, etc.. I also like to have fresh oil in the car. If all this is up to par, you shoould have no problems going through. Hope this helps. Good Luck.

And run the heck out of it to the inspection station. It also wouldnt hurt to use some GM Top End cleaner.