Many texts on time management recommend categorising and prioritising tasks. This is rarely useful for teachers - everything tends to be important, or urgent, or both. Any exceptions - unimportant work - are usually identified and dumped immediately and instinctively.
There is some value, however, in stating the obvious, so here is a summary of the sensible approach most teachers already take to categorising their work.
The matrix shows the four categories of non-teaching task which a teacher has to deal with, and our main concerns are on the 'Important' line. In most schools, tasks in the top left quadrant (Urgent-Important) get done as a matter of course; the focus of the school management team will ensure that action is taken, even if some feathers are ruffled in the process. If you are reading this web-page, your problems are likely to be in the top right quadrant (Not Urgent-Important). If you have problems in meeting deadlines which creep up on you, which then must be tackled in a rush at the last minute, you need to analyse your own working pattern (and your personality) to identify what you need to do. Techniques are listed here.
If you are a hurrier-and-worrier your underlying problem is likely to be in the bottom left-hand corner. You tackle each problem as it comes, prioritising urgent tasks over important ones. This tendency may often be mixed with good intentions - helping other people with their urgent issues rather than focus on your own important tasks. You may find it difficult to motivate yourself until a task becomes urgent. It's as if you enjoy the energy of the last-minute rush as a deadline approaches. The answer to this is simple, but often difficult. You need to cut out the crap, even if it is urgent crap. Use your Yearly Plan to identify and prioritise important projects and do work on them every day until they are complete - even if the deadline is still two weeks away. When that important task is complete, focus on the next important task.
If you are a do-it-tomorrow person, your problem is likely to different. You may not, by nature, be a planner or a well-organised person. You therefore rely on the organisation to determine your deadlines and prioritise your work. This may work most of the time, but unless you allow some contingency, you risk leaving a task too late, and being unable to complete it on time. You should practice time-shift planning (read about it here).
It may not be obvious immediately, but your reputation in school is largely determined in the bottom right hand corner. This kind of work is often done with or for the school support staff. It might be an audit of PC equipment, removing a wall display to allow cleaning, filling in a form for the librarian, or updating your telephone contact details. There are a host of tasks like these in a school, none of them in themselves particularly important. They are, however, a solid way to establish your reputation as an effective and reliable member of staff. If someone needs to be reminded twice about everything, or never co-operates without delay, word gets round pretty quickly.