There is no doubt what is the most problematic aspect of TM4T, and the greatest hurdle you will need to overcome in becoming an efficient teacher: You.
Most teachers join the profession because they want to make a difference to young people's lives, and they are prepared to work hard to do so. There are, however, clear limits to how much productive effort can be spent in any job, and trying too hard or working too long can be - literally - counter-productive.
Not only do overworking teachers achieve less, they can trigger a negative emotional cycle which leads to guilt and stress. In order to be as effective as possible, teachers need to manage their time and stay in control of their lives. This does not mean that they stop being conscientious; on the contrary, by maintaining a clear understanding of opportunity cost teachers can maximise his or her contribution to their school and their students.
You therefore need to be aware of the fact that the average teacher will place higher importance on educational matters than most people, and frequently higher importance than logic dictates. This comment doesn't apply to all teachers, of course, but being over-conscientious is a common trait. This tendency can affect every aspect of a teacher's non-contact life: prolonging parental phone calls, stretching meetings beyond a sensible duration, and making report-writing an agonising search for synonyms. How many different ways are there to say 'must try harder'?
Read a short anecdote illustrating this here
You may sensibly ask what practical use this insight offers. It is one thing to be 'aware' of your tendency to be over-conscientious; it is another thing to be able to use this knowledge. In practice, you will need to review how much time you spend on open-ended tasks like report-writing. In this context 'open-ended' tasks means tasks that do not have clear-cut completion criteria: it is always possible to make a student report even more informative, even clearer, even more insightful. In tasks like this, you need to use the business concept of satisficing; doing enough to satisfy your customers, and accepting that the law of diminishing returns applies: each minute of additional effort you do will give you less benefit.
Many teachers may feel that this is obvious stuff, that they already make common-sense decisions to avoid spending too long on straightforward tasks. After all, no one has remarked on this in school. Well, maybe - we are all different. However, remember that teachers have very little access to sensible external advice regarding the work that they do: neither anxious parents or school management are likely to be entirely logical regarding an over-conscientious teacher.
It is therefore entirely logical that you monitor this aspect regularly. Ask yourself: 'what is the worst that could really happen if I spent a bit less time on this work?'