Though I did have a demo at a potential customer recently, this isn’t about them. These are just the things that I’ve seen repeatedly. I’m not sure what the answers to some of them are yet.

1. The (potential) customer always wants to see 90% of the functionality in the demo – no matter how custom that development is. (This is a case of managing expectations)
2. The complexity of the demo is inversely proportionate to the time available to build it. (Beat the salesman until he understands, then cut all the complex bits and proceed as above)
3. The customer will want to see all logins for all the different users in a process used – and will then yawn as you switch between accounts (and yes, I know about ‘Run As…’. Even so, they’ll yawn). (Don’t show it. Or do it once, and then explain that you’re going to stop switching for the sake of sanity/getting to lunch on time)
4. The bit that you spend ages on getting working because it “must be shown” won’t be shown. (Try to find out how important these hard parts really are)
5. The bit that you spend 5 minutes on, doesn’t do anything, but looks pretty will get them really excited. (This is good! Make sure you show them the exciting stuff)
6. The customer will be utterly confident that they know their business process – and then through the course of the demo show that they don’t. (Try to help them see this, and consider re-engineering/redfining the process. If they won’t, steer clear or work on a T&M basis…)