Obviously you can't force people to be interested, but they can go away saying 'That was a really good presentation' and how do you do that? Well, for me，the golden rule is, don't run over time. Whatever it is you want to say and however much time you have to say it in, as soon as your time is up, stop. You only lose them after that!
I'd advise making a clear outline of what you want to say beforehand on paper ... to make sure you don't forget anything. Then categorise the points and come up with words - like a code - that'll remind you about what you want to say. Then practise it as much as you can, so that in the end you hardly have to look down and the audience can see your face.