How can introvert person improve communication skills?

I admit the fact I'm introvert but it's not that I want to be quiet, I do want to talk and be goofy. But I'm too worried about what others might think of me and deep down lack confidence since I have nothing to be proud of. I don't have any accomplishment or anything going on. And people automatically assume as if I'm good person and mature but in all honesty, I don't even think this way. I'm failing on my life extremely