I'm sorry you feel this way. A lot of people feel like you when they meet new people, as though they have nothing very much to say, but I think if you are always kind and smile a lot people will come to you.
But you also have to put the effort in yourself: if you feel you're getting on with someone you meet (at a playgroup, a hobby group, wherever), suggest you meet again for coffee. It's easier if you have children; people might be freaked out if you did this after bumping into them once at the supermarket, but if you see someone a couple of times and feel you have a connection there's no reason why you shouldn't suggest meeting up, or going on for a drink immediately, for instance (so you don't stew about it). It's nerve-wracking, it's like a first date, but one in five times it might just pay dividends. There's no shame in not getting along with everyone.
Don't be too kind. True friends won't take advantage of you. And remember everyone loves to talk about themselves, so ask lots of questions (about their children, their career, where they studied, how they met their husband, what their new year's resolutions are) and listen to the answers.
Do things that you enjoy (whether that's a swimming class with your baby, or knitting club, or water skiing) and you'll meet like-minded people, and you'll also always have something to talk about.
Good luck. You don't need many friends and life's too short to worry about what people think of you when you put yourself out there (hate that phrase, sorry... But not sure how else to put it!). Be bold, be interested, be kind.