Read the article here.
Shallow work is little stuff like email, meetings, moving information around. Things that are not really using your talents. Deep work pushes your current abilities to their limits. It produces high value results and improves your skills.
And Dan Ariely is quoted in the article:
…it turns out that most people are productive in the first two hours of the morning. Not immediately after waking, but if you get up at 7 you’ll be most productive from around from 8-10:30.
And something I definitely agree with:
Habits emerge from the gradual learning of associations between an action and outcome, and the contexts that have been associated with them. Once the habit is formed, various elements from the context can serve as a cue to activate the behavior, independent of intention and absent of a particular goal… Very often, the conscious mind never gets engaged.