Adopted Tim Pope's Git commit message style. Also enabled Emacs's git-commit-training-wheels-mode:
(use-package git-commit-training-wheels-mode :ensure t
:commands (git-commit-training-wheels-mode))
(use-package git-commit-mode :ensure t
:config
(add-hook 'git-commit-mode-hook 'git-commit-training-wheels-mode)
:commands (git-commit-mode))
Another great post by Chris Beams.