[philippz]

This question is a bit unspecific.

Getting to be a speaker is more than just being good at public speaking. It's about building a personal brand. For that you have to start sharing your knowledge. Start blogging, share what you got to say and try to get some outreach on the web. Start offering to talk in your company and at local tech-events in your city. Finally, watch out for "call for papers" from bigger conferences and start speaking there. What also helps is a great network from people who already are speakers in your field and a network to those who are organizing those events.