You must read N.K. Jemisin's Guest of Honor speech from WisCon 38. There's nothing more I can say than to read it and then take up her call to action in all our lives.
And if you're not familiar with Jemisin's work, I suggest starting with The Hundred Thousand Kingdoms. A few years ago I urged Hugo Award voters to select this work in the Best Novel category. While that didn't happen, I still believe Jemisin's Inheritance Trilogy is one of the best works of fiction to come out of the SF/F genre in years. (I also believe The Hundred Thousand Kingdoms is the only one of that year's Hugo finalists which has actually held up, and yes, that includes the novel which ended up winning the award. But that's a discussion for another day.)
Update: I also suggest people read K. Tempest Bradford's introduction of Jemisin and Hiromi Goto's GoH speech.