How to Deodorize a Room

We've all been there. Your room has 'acquired' a smell, and you just can't seem to get rid of it. Things that are clean generally shouldn't smell, but some odors have a way of getting all over everything. Here are several ways that really work to lessen odors in a room, in order of effectiveness and relative ease. Use the ones that seem most appropriate to your situation, but for really bad odors it may be worth using multiple methods to attack the smell. Finally, don't panic - these really do work and with a little time and effort the odor can be significantly reduced in a couple of days.
How to Deodorize a Room