Decide what you want the outcome of the meeting to be. That means more than just hoping to impress and get an account. Know specifics. Set three definite goals that you want to achieve. Perhaps, you want to show the person you're meeting that you're accomplished, yet humble. Although that sounds vague, it will be easier to manage than thinking of your overall goal of closing the deal throughout the meeting. Make the end goal your main focus, but have some other important goals to achieve in the meeting as well.
Be honest in your business meeting. If you promise more than you can deliver, you'll end up with poor performance feedback and negative word of mouth, not to mention a botched job. If you cite past work that wasn't done, you may get stopped in your tracks. It's ultimately a small world, and a lie will easily come back to haunt you.
Keep positive. Never bash former employers. Even if your business partner cringes and starts bad talking about an obviously unprofessional past client of yours that you also hate, keep your professional persona. Think of one positive thing to state about everyone on your resume. If the conversation starts to go there, acknowledge the person's negative opinion, yet sway gently back into the positive statement. You'll then want to change the subject. If you're not indulging a gossip who wants you do to so, don't let them focus on that setback. You want to keep all parties engaged throughout a business meeting.