If you want to be interesting, you must be interested.
Be interested in everything; be interested in current events, in culture, in daily life. Be interested in new ways of doing things, in activities you’ve never tried, in subjects you don’t know much about.
Definitely be interested in the people you are talking to. The more interested you are about them – the more questions you ask them and the more opportunity you give them to tell their story – the more interested they’ll be in you. They’ll wonder why it is that you are so interested in them, why you are giving them the precious gift of time and attention. They’ll start to wonder about you, ask you questions in turn, and remember you in greater detail.
The key is to make this interest genuine. It may seem next to impossible to display real interest in something you find really dull, but usually there is at least a silver thread of fascination in just about any topic. If you find yourself having difficulty finding a subject interesting, drill down into it and find some way that it affects you on a personal level. If the person you are talking to is desperately boring, ask them questions and then ask more questions for every answer until they reveal some odd or delightful nugget. The fact that the interesting nugget is unexpected will make it even more interesting. If you are having trouble finding some glimmer of interest in that person, you either haven’t asked enough questions or you aren’t really listening to them. We humans are an odd bunch, which means endless opportunity for fascination if you are willing to look hard enough.
Approach just about everything you encounter with open curiosity. The interest-rebound effect that it has on you is due to the fact that it expands your worldview, increases the breadth of subjects you can converse about, and encourages others to be interested as well.
The added advantage, of course, is that it also makes life a whole lot more fun.