Know your audience. Knowing who you're talking to and what matters to them should be the driving force of the presentation. This slant alone can make the difference between pulling your audience in and pushing them away. Sure, you might have valuable information to share, but if it's not geared to the people sitting in front of you, they're going to tune out.
Know your product. The content sweet spot lies in the crossover between what your product can do or offer and what your group wants. Listing a bunch of random features or, worse yet, seeming ignorant of your product's attributes, will make you look unprepared at best. At worst? You'll come across as unqualified.
Plan ahead. Prepare your presentation. Don't just make it up on the fly. This should be a no-brainer. Even if you feel good about your improvisational capabilities, you should know how you're starting, how you're finishing and have plotted out a path to get there. If you opt to follow your audience's lead and go off the path, that's fine. Just have a roadmap.
Choose a focus. Most presentations aren't long enough to be completely exhaustive. Decide what your audience needs to know, wants to know and what they'll be surprised or impressed by. Everything else is details.
Speak clearly and professionally. Skip the "ums," "uhs" and "you knows." At best, they are distracting. At worst, they undercut your message, not to mention your professionalism.
Be prepared for questions. Otherwise, you'll underrepresent both yourself and your product. If you don't know, say "I can find out for you." Your audience will appreciate your honesty, not to mention your willingness to go the extra mile.
Arrive early enough to familiarize yourself with the equipment. Not all tech set-ups are created equal. Taking part of the presentation time to work the bugs out wastes your audience's time and undercuts your credibility, not to mention adding to your own anxiety.
Don't make promises you can't keep. No product is all things to all people. We get that. Be honest.
I could go on (believe it or not), but I think you get the point and, if all of these pieces are in place, you're in pretty good shape.
What would you recommend to someone who wanted to take their presentation to the next level?