A while ago I described my elevator pitch – short description of what I do that can be delivered to a stranger. It assumes that they know nothing about me or what I do and can be shared in the time we share an elevator ride.
The folks over at Freelance Switch have developed a useful guide on creating an elevator pitch that’s worth a look.
They offer several tips but this is the big one in our view.

Once you’ve put something together, practice it. The trick with an elevator pitch is that while it’s planned, it needs to sound spontaneous; not robotic. Practice this by saying your pitch while your in the car or shower, making sure the words are natural and it’s easy to remember.

We’d also suggest trying it out loud in front of a mirror and then running it past a family member or friend who doesn’t understand exactly what you do.
Having a couple of different versions is also handy. I think a long version that lasts about a minute and a one or two sentence “highlights” version work well. For example, my short version says that I am a professional communicator that helps people tell their story. If that piques the listener’s interest (it usually does – who doesn’t like a story teller?) I can go with the longer version.
A solid elevator pitch needs to be memorable without being ridiculous. You want potential customers to remember you for what you do and stand for, not just because you were funny. And make sure you back up the pitch with a business card that tells people what you do and not just who you are. Consider it your paper-based elevator pitch.