A lot of the research and theory underpinning time management is focused on the individual. YOU. The key fact is that you - like all humans - can be remarkably productive in some contexts, and astonishingly UNproductive in others. Obviously, environmental and other factors have an effect, but the core of the problem is right there: YOU.
This is - I'm sure you have noticed - a short page, and there is an important reason for this. Some of the time-management problems we face require an in-depth understanding of principles, others require practical techniques, whereas others don't demand any particular knowledge or insight - there's a set of methodical steps to follow. In the world of self-awareness, it is all about techniques, tools that you can deploy in a variety of situations to ensure the best possible YOU is in action. Most of the material on this topic is therefore in the corresponding Techniques section of this website, which is here and we're not going to repeat any of that material here. If you really want background and theory, then Mr Wikipedia is yer man, and here are a list of the topics that we cover in our Techniques section:
The four techniques of insight:
You need to understand your conscience and guilt
You need to understand your chronotypes
You need to understand your attention span
You need to understand your personality type (and its strengths and weaknesses)
and the four techniques of action:
You need to understand how and if Relaxation can offer benefits
You need to understand whether Habit is a friend to you or not
You need to understand what benefits Mindfulness can offer you
You need to understand how a change of Mindset can help you cope
As always, TM4T declines to compete with Wikipedia. Use the italicised words if you want more academic background - there are also useful links in the Techniques section.