Have you started making changes and than realize that you should have created a new branch first. Well, there is a slick way to create a new branch and have those changes ‘moved’ to from master to your topic (the new branch).

git branch newbranch
git reset --hard HEAD
git checkout newbranch

This works even if you have made commits to your local branch, just subsititute HEAD with the number of commits back you would like to go, i.e. HEAD~2, or use the SHA.