My wife and I were there two years ago. Some thoughts:

1. If you have the Museum Pass for a number of placers in and around Paris, check out the discounts for Versailles;
2. Get there the minute it open s up and before the busses pull in (Mondays and Tuesdays are preferable;
3. Plan on spending a day there. If you need to see every room, it will take that long.
4. Watch out for pickpockets in the main square. They will try to distract you and take something of value to you - like your camera. Keep your stuff closed and don't speak to anyone except an official tour agent.
5. If you have the energy, plan to visit the gardens and Marie Antoinette's Petit Trianon. It might be worth an extra day just for that.
6. Train ride to and from Paris to Versailles is easy and inexpensive. The Versailles Gare is about 2-3 blocks from Versailles. Hard to imagine Louis XIV wandering around the outskirts of his palace.
7. Enjoy your visit. Bonne journee