Development as a whole is a people job, most of your work involves getting in touch with other people, by getting their opinion, solving some of their needs or reaching out for help.
Also, most of us, love our craft, our tools, our languages. This creates the innate need for people to share their interests, hobbies and experiences.
Therefore, communities were created.
Joining a Community
The first step of getting involved is joining a community. To do this, there are plentyful of ways. Most communities have gatherings, conferences, mailing lists, forums or IRC chats. You can participate by joining to either one or multiple of this communication channels.
Just by joining the community, you already get benefits, you get to know what the community is talking about, what are the main interests, who are the most relevant members and the most interesting projects. This already gives you a great hint in what you can contribute back to the community.
How to contribute
There are multiple ways for contributing to a community, each has their own, be sure to research them. But most notably, the majority of the communities have a list of ongoing projects, job-lists and gatherings in which you can collaborate and contribute to. Also, you can propose your own projects if they fit the culture.
Another great way of contributing is helping people with their doubts. Helping to solve another persons problem is really benefitial when done in a public environment, as it stands for a great documentation source in case something similar happens to raise up again.
Benefits from contributing
A great part from contributing is that, in some way or form, you're always getting something in return.
The first thing you'll get back from contributing is the joy of helping out other people (and many times yourself).
Another great benefit is that you will be participating in whatever is hyped by the community, which will polish your skills in that matter to the maximum possible.
By helping out members, you're most likely getting exposure, your name will start popping up more and more frequently when in need to do something. This is really great, because it gives you a lot of opportunities to keep contributing and also the possibility to get known outside of your community.
As our job is mostly interacting with people, try as much as you can to get involved in every community that you're interested in.
The joy of helping others and getting to know and learn what's trendy is one of the best return on investments you can put on your time and effort.
So my advice is, start reaching out to your community, you'll get a kick out of it.