Everybody is afraid to talk to strangers. Its just that some people start a conversation and make it convenient for others to talk.
Simple way to start is to go to meet ups which discuss your tech subject. Ask questions and let them talk. You will soon get yourself involved in the talk. People love to talk. Not many people listen
If you lend your ears and ask them about themselves, you will learn a lot and earn friendship of people and eventually you will be able to talk to anybody. Remember "Half of the world is waiting for the other half to say hello", So just start with a anything, a question, a smile, a remark, an appreciation, anything!