There are different ways in which you can influence the dev community.
Become a Mentor. By reading questions and writing relevant and extensive answers, you can help many people directly, and even indirectly, because people with the same problem as the OP might find your solution and be grateful! If you want to contribute even more, write a story or blog post which explains an interesting aspect of some tech, your personal take on a real-life problem.
Become a FOSS Developer. Create useful software, like a library, a framework or an application people need. Join one of the many projects on platforms like GitHub and help develop useful software. Most of the time, we developers want to solve a high-level problem (like displaying stats from a DB). We don't want to worry about how the data is stored or how to connect to the MySQL server. That's why we use libraries which provide the necessary functionality. By providing such a library, you can help thousands of developers!
Become a Networker. Write posts on Twitter, Facebook, Google+, etc. Share your opinion about a "dev-political" problem or an interesting story from your daily life. Everyone loves to read about someone else's life, problems, solutions and opinions. Help people stay up2date. Share important statements of other important people, in order to get the word out about interesting news and developments.
Most important of all, however: communicate, be open, be open-minded and be honest. Even if you think that you are just a single person and not a lot of people seem to follow you, you still help many people and the number will grow as long as you give it you all.