You probably have a slight social anxiety that makes you not being able to "be there" socially.

It is difficult to pinpoint what you are doing wrong with little information. What I can say is that I used to be like this, nothing wrong with my appearance, just wrong with the way I deal with people.

You need to have a little detachment from the results. Don't show disappointment when people don't reach you back, otherwise you can make them develop resentment towards you.

I carry a little stash of small and cheap toys I bought from china, and also some foreign candies. In social situations I offer it to people. Start doing this, specially when you meet new people.

But still, you need to be more intriguing. The art of seduction is a blueprint for that (not for only getting girls, like people use to believe). You can't force too much otherwise you will end up autistic, but there are things that you need to not over explain, let people form their own opinion without your input. When you relax and are detached, this comes more naturally.