When we have social anxiety our first reaction is often to avoid social situations because they can be stressful, but this just puts us into a vicious cycle: We avoid social situations, our social skills deminish from lack of use, we avoid social situations even more because we feel inadequate in them, our social skills get worse, and so on.
I think we all know deep down inside that socializing can be enjoyable and we all want to be able to do it. The best way to deal with social anxiety is to change your negative automatic thoughts and anti-social behaviors. One of the best behaviors to practice is to get out there and talk to people. You'll find that most people are friendly when you start a conversation. A great way to start a conversation is to say hello or to give someone a compliment, like "nice hair", "or i really like your dress", or nice shoes, where'd you get them?", etc.
Good places to meet people casually is at the gym (and getting some exercise in is never bad either), at the supermarket (and buying some healthy food is never a bad idea), at the park (and getting some fresh air and sunshine is never a bad idea) or on public transit. Most people just sit on the bus or the subway and awkwardly try to avoid eye contact with eachother. Why not pay the person across from you a compliment instead?
Your social skills will get better the more you use them and you'll become more confident as you realize that most people are friendly. Don't let one negative response deter you. Some people are just in a bad mood sometimes and some people are just mean. Just don't take it personal and move on to the next person.
If you want to meet like-minded people on the internet you can put out an add on Craig's list. If you like art look for someone to go look at some art with. If you like soccer, try to start a soccer game. If you like heavy metal, look for someone to go to a concert with, etc. Remember, there are tons of people out there just like you who are socially anxious and want to have more friends to hang out with.
Hope you're feeling present and calm