Avoid drinking water that comes out of a shower head. Research shows that the shower head is full of germs and coupled with bacteria from the shower's hot water heater, it is no water fountain.
Try closing the lid to the toilet when you flush. Germs become airborne otherwise. Eww!
A bathroom fan can do more than eliminate odor. Another way to remove mildew and avoid allergy irritation is by ventilating properly. Let your fan run at least 10 minutes after showering, definitely longer if you still see moisture on your walls.
Keep your toothbrush in your vanity - never leave it out on the sink or anywhere that airborne germs can get a hold of it. If your bathroom is small enough, germs from your toilet can definitely reach the toothbrush.
Avoid cleaning your ears with Q-Tips. The cotton swab has many uses - but cleaning your ear can be a hazardous one.
The towels at your friends' house may look welcoming - but if you use them to dry your hands after washing, you are essentially passing germs back and forth. Opt to use paper towels or a tissue, which can be discarded.
If you suffer from asthma, you may want to consider keeping the shower curtain open. By airing out the shower, you are letting it dry out and avoiding mold and mildew build-up.
Always keep your contact lens case clean by disinfecting it (use your saline solution to do this), and try to change the case every few months. Bacteria builds up on the case, especially if you keep it out in the open. Dry the case through after cleaning to avoid further bacteria growth.
When rinsing your mouth, use small paper cups, which can be disposed of, instead of plastic, reusable ones that can collect germs.
The amount of times you are in and out of your bathroom certainly merits it special housekeeping attention (not to mention what we do in it). Here are 10 tips to ensure your bathroom is a place to get cleaner, rather than dirtier.