Scheme:

<your initials>/<ticket reference>-<description>/<number>-{explore,proposal,…}

Example:

rm/gt1648-make-tests-pass-under-karma/1-explore

Advantages:

• The output of git branch stays neat, even when you work with many branches.
• The initials allow you to identify your own branches. This is helpful, for example, when you use git retire to keep the repo clean. You wouldn't want to delete your coworkers' branches.
• It will be easier for you to go back and see everything you explored for a certain ticket.
• The numbered explore- and proposal-branches allow you to rebase and squash and edit freely while keeping other lines of exploration intact. Without this, you would have to dig through the reflog to undo a botched rebase.
• As the branch name contains the issue number, it's easy for your colleagues to find the changes that belong to the in-progress tickets.
• In general, when you push your feature branches to origin and your colleagues run git fetch origin, your branches show up in their branch autocompletion list. By using a common scheme, the contents of the autocompletion list will be predictable.

Details:

• If multiple contributors have the same initials, you'll have to find different shorthands.
• The ticket reference can be the issue number in Redmine, a board shortcut plus card number in Trello etc. See also Per-issue directories.
• explore is for branches where you're poking around. proposal is for when you make neat commits that you will git-send or open a pull request for. You can use other labels, too, eg. test.
• I used to recommend fix/feature/nonfimp instead of your initials as a prefix. That turned out to be less useful.

I suggest composing this with git retire.