You don't get a lot to work with here, so you better make it worthwhile. (This is the name of the Twitter game if I haven't made that obvious yet.) You have 140 characters to explain why someone should follow you, so this is the first place you can make it clear what you will be tweeting about, what you want to read tweets about as well as do all the things a profile usually does (establish credibility, allow identification, create interest, etc).
1. A clear photo - these are really small in the feed so just your face is usually ideal. A nice background is cool if it is super simple, but not necessary.
2. Links to your affiliated companies twitter accounts (if any). See Eric W. Dolan's profile as an example:
3. For companies, write your one-liner motto and put in contact info using shortened URLs (more about that below). See @Rackspace for a good example:
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