1. Buy a bath fan. What's the most important thing in a bathroom? It's hard to argue with a toilet and some running water. But after those (and before you add a shower), you need a bath fan. I'm amazed at how many bathrooms I go in that don't have one. A window is not enough, and a small noisy fan that nobody wants to turn on is not going to do you any good. Buy a good, quiet bath fan, and if it doesn't have an occupancy sensor, wire it with a separate timer switch. A fan should run for at least 10 minutes after you leave the room for odors and 20 to 30 minutes after a shower. Make sure it vents to the outside. Though it's important to have a certain level of moisture in the air in your home, it's not good to have it all in one place. Vent your bathroom and your paint will last longer, you won't run the risk of mold growth and cleaning will be easier.