diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index a2d3f87..86f023e 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -1,7 +1,8 @@
 Contributing
 ============
 If you would like to contribute cheetsheets or program functionality, please
-fork this repository, make your changes, and submit a pull request.
+fork this repository, make your changes, and submit a pull request against the
+`master` branch.
 
 
 ## Python standards ##
@@ -22,4 +23,7 @@ tar -cvf /path/to/foo.tar /path/to/foo/
 tar -xzvf /path/to/foo.tgz
 ```
 
+If you are submitting a cheatsheet that contains side-by-side columns of text,
+please align the columns using spaces rather than tabs.
+
 [PEP 8]: http://legacy.python.org/dev/peps/pep-0008/