If you have standup later in the morning/afternoon, or you work remotely in another time zone than your team, this can prove to be especially handy. Make sure you let your team know what the file is if you're going to be getting online before everyone else the following day, especially when first starting out. This will help you stay focused, have clear direction, and plenty of work already imagined for yourself that day.
At the end of your day, find a place in the codebase that has open, assigned work pinned to it via a story. For an added bonus, open the files in your editor, and simply put your computer to sleep.