Every teacher, no matter their experience level, has something they can share with others. It may be something little, like a trick they've used to get students back into a lesson after lunch, or something big like using Genius Hour projects to change the world. I have become so passionate about encouraging teachers to share what they know because it so rarely happens, and we are so rarely given forums in which to do this.
So, I encourage you to find some way to share what you know. Obviously, it will benefit others, but it will benefit you even more. When teachers teach teachers, they gain confidence in what they are sharing and doing in the classroom, which in turn, encourages them to try more new things, and share more. Sharing leads to more sharing. Some ways that teachers can share their knowledge include sharing ideas and links on Twitter, offering to present on a subject for a professional development session at their own school or district, submitting an article to a journal for inclusion, or proposing a session at a workshop or conference. You'll be surprised what you'll be able to do when you ask.
Another way that I highly recommend is going to an Edcamp unconference. No matter where you are located, there is likely an Edcamp somewhere near you. (I coordinate our local EdcampPHX event, though there are hundreds of Edcamps around the world.) These unique gatherings feature teachers as the sole content source. There is no sponsorship and no presenters determined in advance. When participants show up in the morning, they gather together and make a list of sessions they would like to participate in that day. From there, those sessions become the schedule for the day. Anyone who suggested a session simply agrees to get the discussion going on the chosen topic, and everyone in the circle is encouraged to share their expertise. No consultants, just teachers talking to teachers. At every Edcamp I've been a part of, teachers are floored at how good it feels to be validated for the knowledge that they do have, and to learn from other educators.
One of the first lessons I learned in teaching is, "Close your door and do what's right for kids." Please do what's right for kids, but the best way to get better at what your doing is NOT to close your door. Share your hard-earned knowledge with others, to save them the sweat and tears. Then listen to them, and learn from their wisdom as well. I want to say, "Next time someone asks you what you can share with other teachers, I hope you have a positive reply." However, unfortunately, our system doesn't often encourage teachers to share with others publicly, so you'll likely have to speak for yourself. So instead, I say, be bold. Your knowledge and insight could change another teacher's (and student's) world.