Good bathroom etiquette is largely a matter of common courtesy. By taking a few easy measures for the comfort and benefit of anyone else who may use the same restroom, you create an atmosphere where your compatriots will be inclined to do the same. (We hope.)
When occupying a stall in a multiperson restroom, issue a courtesy flush. In other words, flush the toilet while you're still using it. This simple maneuver will cut down on the smell, not to mention the chance of someone passing out at the first whiff of trouble. And while we're at it, check the bowl before heading out in case you need to give another flush so that the next person doesn't have to deal with something you accidentally left behind.
If you're using a shared single bathroom, kindly flip the fan switch before you take a seat. This is for both your immediate benefit and that of future visitors [source: Schulz].