Contributor guidelines

README.md

 xBOUT examples
 ==============
 
-A set of self-contained examples showing various features of [`xBOUT`](github.com/boutproject/xBOUT).
+A set of self-contained examples showing various features of
+[`xBOUT`](github.com/boutproject/xBOUT).
+
+Contributor guidelines
+----------------------
+
+In order to make the examples easy to use, we keep them in a single repo and do
+not use git-lfs. That means we need to stop the repo from getting too big. We
+also want the examples to be self-contained, so people do not need to have
+BOUT++ set up and running before they can run these examples.
+
+Some guidelines for making examples:
+
+* Ideally the code and inputs to create datasets should be publically available
+  and linked from the example.
+
+* Even if the code is available, the dataset needed for each example should be
+  archived on [Zenodo](zenodo.org) so that the example can be run
+  independently.
+
+    * Please provide a setup call to download the data from Zenodo if it is not
+      present.
+
+* We will use squash-merging of pull requests to minimise the number of data
+  objects (e.g. plot output in Jupyter notebooks) present in the history.
+
+    * We should also try to make PRs with significant changes as complete as
+      possible before merging so that we minimise the number of PRs that make
+      changes to data objects.
+
+    * Small PRs fixing typos, etc., should be fine as long as they do not
+      modify data.