This one works a couple different ways, depending on your time and inclination.
The easier one of the ways is to wander to your spice cabinet and pull something at random, then sit down and inhale over it.
Another way is to go to the perfume counter at the store and find something and sniff.
Bonus points, go to a fine department store, such as Macy's or Nordstrom or something. Rather than stopping in the regular makeup area, go to the Parfum section and ask to have a consultation. They'll spray stuff on little cards and let you sniff. Bring your notebook and take notes.
Write whatever comes to your mind, memory or dream. See what comes out of your pen.