Mashable: Choosing Twitter hashtags, an infographic
Previously, we’ve discussed how to use Hashtags on Twitter and Facebook. This might still be a difficult concept for many to grasp. To make things easier for us who learn visually, Mashable posted a very informative infographic that leads you through the process.
Start out at the top, and follow the arrows (based on your hashtag goal). Throughout the process, you are asked to ponder a bunch of different questions that will lead you to the best result. The flow-chart will even help you figure out if your Tweet or Status Update would benefit from a hashtag at all.