How do i improve communication skills to think of more things to say to people?

i have a problem when im hanging around people not just friends but everyone. sometimes when im wanting to talk to someone i can never think of anything to say. so it makes me afraid to call someone or go up to talk to them cause im afraid that it will end up in dead conversation. it also makes me afraid to end up in a relationship cause im afraid that she will lose interest in me because of the lack of my communication skills.

I don’t think your problem is on a "communication" level, per se. If you cannot think of anything to say, well, that’s different than "there are so many things I want to say but I don’t know how".
Many people have this problem, anyway. I’d suggest the easiest way out: read about mundane stuff, things that people might know and relate to, and strike a conversation that way… For example:
"So, what do you guys think of the Olympics, this year?". Just an example. Of course, you might want to educate yourself on what *is* going on in the Olympics, so that you might have further input to add as the conversation moves along.