Great line from Dale Carnegie's Influence book, "better to be interested not interesting." However, getting there is tougher.
#1 Nothing beats a Smile: You smile at people, they smile back. They also feel warmer with your smile.
#2 Give Compliments: Notice something about them on their person. If it's a woman, jewelry like, "that's such a beautiful necklace, how did you get it? I was thinking about getting one for my sister/mom/friend." People love compliments about their style -- it validates their good taste and they'll reflect that on you.
#3 Take Notice about What Makes People Tick: I tend to ask questions that will always bring a second response and follow up question. They usually start with "Tell Me what was..." For example, Tell me what was your best concert ever? Tell me what your best moment of the year was in 2015? Best moment of the summer? Whatever they come up with, that gives you a vision on what is important to them. Could be family, heavy metal music, traveling or whatever... it totally becomes a great vision into it. Follow it up with a question like, "wow always heard Zac Brown puts on a great show. What makes his concert so over the top for you?"
Above all, notice their body language. If they don't turn more than their head towards you, even when it's a subject they love to talk about, they're not interested in talking to you, or at least not right now. Don't take it personally.
If you're dating and talking to people at bars, etc..., be happy with quick rejection. You never spent time money or energy on them. And you got to move on to the next opportunity fast.