diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
new file mode 100644
index 0000000000..a03cfdda48
--- /dev/null
+++ b/CONTRIBUTING.md
@@ -0,0 +1,31 @@
+# How to contribute
+
+Howdy! Usual good software engineering practices apply. Write
+tests. Write comments. Follow standard Rust coding practices where
+possible. Use 'cargo fmt' and 'clippy' to tidy up formatting.
+
+There are soft spots in the code, which could use cleanup,
+refactoring, additional comments, and so forth. Let's try to raise the
+bar, and clean things up as we go. Try to leave code in a better shape
+than it was before.
+
+## Submitting changes
+
+1. Make a PR for every change.
+
+   Even seemingly trivial patches can break things in surprising ways.
+Use of common sense is OK. If you're only fixing a typo in a comment,
+it's probably fine to just push it. But if in doubt, open a PR.
+
+2. Get at least one +1 on your PR before you push.
+
+   For simple patches, it will only take a minute for someone to review
+it.
+
+3. Always keep the CI green.
+
+   Do not push, if the CI failed on your PR. Even if you think it's not
+your patch's fault. Help to fix the root cause if something else has
+broken the CI, before pushing.
+
+*Happy Hacking!*