update the contribution guidelines

CONTRIBUTING.md

@@ -4,12 +4,14 @@ Your contributions are always welcome!
 
 ## Guidelines
 
-* Add section if needed.
-    * Add section description.
-    * Add section title to Table of contents.
+* Add one link per Pull Request.
+* Add the link: `* [project-name](http://example.com/) - A short description ends with a dot.`
+    * Keep descriptions concise.
+* Add a section if needed.
+    * Add the section description.
+    * Add the section title to Table of Contents.
 * Search previous suggestions before making a new one, as yours may be a duplicate.
-* Add your links: `* [project-name](http://example.com/) - A short description ends with a dot.`
 * Don't mention `Python` in the description as it's implied.
 * Check your spelling and grammar.
-* Make sure your text editor is set to remove trailing whitespace.
-* Send a Pull Request.
+* Remove any trailing whitespace.
+* Send a Pull Request with the reason why the library is awesome.