Firstly, you need to believe in yourself, and believe in the fact that you CAN be a person with a better self esteem and you CAN overcome social anxiety. :) Humans are not perfect, and everyone has flaws, but we should try to focus on the our good side, which makes us feel more confident. Try to think less about your negative sides and what people think about them;always have a positive mindset, these will reduce your insecurities. Stand straight with a constant smile on your face. :) Now, I understand it can be difficult for you to communicate with others sometimes...but you need to look past what stops you from expressing yourself. To do that, you must first recognize what exactly makes you anxious and then try to eliminate those thoughts with proper reasons. Realize that people are not always judging you or noticing your flaws. Start by talking to a small group of people, and get to know more people, talk to them about their interests, and you will find that its actually not that difficult. You can only overcome the anxiety when you get yourself out there and start communicating, no matter how hard it seems at first. Good luck :)