Clarity
Clarity of communication is one of the most important components of a presentation. A great presentation is clear in intent, communication and articulates a specific point of view. Bonus points for presenting that point of view in a unique fashion.

Drama
Great presentations are delightful in some way. Drama means connecting with your audience in a way that taps into some emotional trigger at a human level—storytelling often does this. One of the most difficult things to do is to present information (even dry information) in a way that is compelling and captures the attention. A certain amount of drama will do this. Basically have fun and lots of enthusiasm, it is contagious. If you are simply reading your paper, no one will want to listen to you.

Design
Visual aids and the overall design of a presentation can really help one stand apart from others. You can take two presentations that have equal amounts of substance, but the one that is better designed is usually the one that has the advantage. Visual design matters in presentations.

Flow
Great presentations seem to have a natural flow to them. It's not forced, transitions are natural and it all just seems to come together. Getting your presentation to flow well seems like it should take the least amount of time but often ends up taking the most, it involves editing, and tweaking that can take your presentation to the next level. This is where the organization of your information really brings it all together, make sure you practice it enough times to work out all of the kinks.

Substance
Of course, a presentation is nothing without great content. All great presentations contain wonderful information. Just as all substance and no flair is a recipe for disaster, so is flair without substance.