I fell upon this article while browsing the web by Gregory Ciotti (a behavioral psychologist). He made a great video of the essential finds from his research on productivity - definitely worth a watch:

The article is quite meaty and takes some time to read but give fascinating insights into some really simple steps to get us doing more with our time - rather than dragging out tasks over a whole day, week or month. I had never considered “willpower” to be an exhaustible resource before! Take some time out to read Gregory’s excellent and simple actionable advice.

Link to the article: http://www.sparringmind.com/productivity-science/