Blocs, Black and Otherwise
This is the classic "Blocs, Black and Otherwise" written by Crimethinc. It's a very good overview of how to organize and participate in a black bloc.
We couldn't find a PDF of it online, so we put this together. As a bonus, we added another piece titled "Fashion Tips for the Brave" that contains more suggestions on preserving anonymity within a black bloc.
Sprout Anarchist Collective