Add branch tips

Git-Tips.md

@@ -46,6 +46,11 @@ More information is available in the [Contributing guidelines][contributing].
 1. Once you're ready, push your local commits (`git push`)
     - for the first commit on a new branch, use (`git push -u origin <branch>`)
 
+# Branches
+
+1. You can delete local branches when you are done with them (`git branch -d <branch name>`)
+1. You can also update your refs to reflect any remote branches that have been deleted (`git fetch --prune`)
+
 # Rewriting history
 
 **NOTE: IF YOU DO NOT KNOW EXACTLY WHAT YOU ARE DOING, DO NOT MESS AROUND WITH THE GIT HISTORY**