The first day of any new job is terrifying, but school must surely count as one of the worst. First of all, you are “on” the whole time. You have to appear competent in front of the kids, and not too much at sea in front of your colleagues. Here are the best tips I can offer:

Bear in mind that every teacher has a horror story, and lived to tell the tale. The first time I ever saw a school year timetable was two minutes before I went into my very first lesson in my new school, with my form tutor group. I was told: there’s the 6th form timetable. You have to make sure they each know where they’re going all day every day.”

“Wait!”, I said. “How? This doesn’t mean anything to me.”

“You’ll figure it out”, came the reply. “Or ask the kids.” So I did, and it all worked out fine. I may have bluffed a bit by saying something like “This timetable is different from the ones I’m used to.” (Not a lie: I’d only looked at bus and train timetables before that.) “Could someone show me how it works please?”

Or take the first three lessons of a Year 9 group on teaching practice. Terrible. I still come over cold when I think about it. But then I thought of a really interesting question to discuss with them, and the fourth lesson went like a dream.

I also found the first few weeks teaching Social Studies to a Year 9 group at my first school very difficult. But that was because I’d been misled, and was not authoritarian enough at the beginning. I’d been told that all the kids in the group had chosen that particular option. That was not entirely true. Of the 30 pupils, 10 had put it down as their second choice, 10 had put it down as their third choice, and 10 had not put it down as any choice: they were there because none of the other teachers wanted them in their subjects. So…
Try to get information about the pupils in your groups. I understand that there’s an issue about not wanting to prejudge people before you’ve met them, but there is also an issue about wanting to go into your lessons with useful knowledge.

It’s not even necessarily just about discipline. For example, if there is a pupil who refuses to talk (an elective mute), you should know that in case you inadvertently put them in a difficult position. You ask them a question, they sit there in silence, and you start shouting or chucking them out of the lesson!

Or perhaps there are really helpful kids, maybe even a “Digital Champion”. All very good information.
When preparing your first day’s or week’s lessons, bear in mind two things. First, the job is more tiring than you think. It’s not just the amount of work, or even the amount of noise in an average school (although they are challenging enough). It’s having to make thousands of very small decisions all day long. In fact, a Health and Safety Executive report in 2017 rated teaching as the third most stressful job in the UK. Think about it: in each lesson you have to decide: What should I do about that pupil fiddling with his pen? Should I ask the pupil with her hand up what she wants? Should I break my flow in order to ask those pupils at the back to be quiet? Therefore, it’s better in my opinion to be fresh and not quite as prepared as you think you should be, than to have the lesson planned to within an inch of its life but be too tired to be creative in responding to something which is not planned, such as the fire alarm going off or the internet connection being lost. However, you should think of a standby activity or two to fall back on should the unexpected happen.

Secondly, there is the law of diminishing marginal returns. In this context, it means simply this: The first tranche of time planning a lesson (let’s say 1 hour) is likely yield good results. The next half hour on the same lesson will probably be very useful, but not as much as the first hour. If you then spend another half hour on it, you’ll have even more material and strategies to work with, but the increase in those won’t be as great as the second half hour compared with the first hour.
Anyway, even if you’re not convinced, think about it in this way: If you have 5 lessons a day, meaning 25 lessons a week, are you really going to spend 2 hours preparing each one? Or even one hour?

Indeed, make one of your priorities learning how to plan lessons in outline, in no more than 15 minutes, and preferably less. If not, you’ll burn yourself out, and be no good for yourself or your pupils.
Find out what the school procedures are for maintaining discipline, dealing with lateness, failing to hand homework in and so on.
Find out what the school protocols are for things like being alone with a pupil (my advice: don’t), and contacting parents.
Start a Twitter account if you don’t already have one, and start following people. My Twitter handle is @terryfreedman if you’re interested. See 10 Things To Do When Someone Follows You In Twitter.
Read the following articles:

Discipline in the classroom: What, Why and How
20 Things New Teachers Need To Know About The Technology In Their School
6 Routines For Computing Lessons
10 Ideas For Computing Or ICT Lesson Routines
If you teach Computing or a related subject, sign up to my newsletter, Digital Education, for summaries of research, resources and reviews.

I hope you found this article useful. And good luck: you’ve entered a great profession!