A huge mistake that many people will make is to get all excited and make their first presentations to major prospects. This can easily spell disaster. Just like a Broadway play, they start out off-Broadway to get everything right.
Start out with a few of your smaller or less likely-to-buy prospects so that you can work the bugs of your presentation out. Small prospects will probably have most of the same questions and objections as big prospects, and you will now have the opportunity to smooth out your presentation before you hit the "big guy."
