One of the things you personally can do to help work against racism in the speculative fiction world is to join the Carl Brandon Society, which aims to increase racial and ethnic diversity in and around science fiction and fantasy through various means and various projects.
If you're not up for contributing financially by joining, though, there are other things you can do to help out, if you're so inclined. For example, you could stop by the Society's new wiki and read and/or contribute to the articles there.
Not sure where to start? Try the Wanted pages list, which I think is an automatically generated list of articles that don't exist yet, but that people have linked to from other wiki articles. (It's easy to do that in a wiki.)
The wiki is only just getting started. Stop by and help out!