Have you been asked to observe another teacher? It can be pretty terrifying for you as well as them: the power to do good is great but so is the possibility of getting it wrong and causing offence.

I have heard of situations where the observer: “Arrived late and disrupted the lesson; “turned up without any notice”; “corrected the teacher in front of pupils”; “looked bored or disapproving - or fell asleep!”; “didn’t give any feedback”; “gave written feedback without an opportunity for discussion”; “made erroneous judgments based on poor knowledge of the context”; “upset the teacher without giving positive ways forward”.

A bad experience will knock any teacher’s confidence. Most people are hard enough on themselves so make sure you see observation as an opportunity to point out strengths and successes.

Observation and giving feedback are very complex skills, which need training and practice. Make sure that you and the teacher are clear about why you’re observing and what the focus is. Is it for appraisal, curriculum monitoring or professional development? What about the notes you make: will they be given to a third party or not?

Don’t observe without giving the teacher notice - what’s the point? Around a week seems fair. Staying for a whole lesson is ideal but isn’t always necessary. Choose a time that the teacher feels happy with and that will give you the information you need.

Agree a time and place to discuss the lesson, giving both of you time to reflect, but ideally at the end of the day.

Don’t forget to ask for a lesson plan. It will probably have to be in greater detail than the teacher needs for you to understand what’s going on.

Choose a lesson observation format that’s appropriate to your purpose and focus - inspection forms should only be used for inspection. Make notes for yourself during the lesson but do a tidy summary of strengths and write up areas for development when you discuss it with the teacher.

During the lesson, notice cause and effect: what was it about the teacher’s delivery that caused pupils’ rapt attention? Think about the learning and how the teaching is helping or hindering it. Note what pupils actually achieve.

Don’t forget that your presence, however unobtrusive, will have some influence on what happens in the room - pupils may behave better, the teacher may be more inhibited than usual. Like a science experiment, you are a variable so you’re not just observing a class, you’re watching a class being observed - and that has an impact on the adults and children.

Try to sit outside the direct line of the teacher’s vision, but where you can see the class and what the teacher is doing. At the side, half way down is best. When the pupils are doing activities, move around to see what they’re doing. Look at different groups (girls and boys; high, average and low attainers; and pupils with English as an additional language or special needs) to see whether everyone’s on task and learning. Ask things such as, “Excuse me, what did Miss ask you to do?” and “What are you learning? Why?”.

Don’t go in looking for problems: weak teaching is very rare so get ready to spot the good stuff. This may sound obvious - patronising, even - but I’ve known so many teachers who sit there thinking how they would have done it.

Read the lesson plan, paying particular attention to the learning objective. It’s useful to annotate the plan, showing what parts went well and so forth. Make notes about what actually happens (with significant timings), focusing on the agreed areas but keeping your eyes open to everything.

Don’t start teaching the pupils yourself or interfering in any way. This is tempting. Pupils will often expect you to help them but if you help one the floodgates will open. This will distract you from your central purpose, which is to observe the teaching and learning. Don’t intervene unless things get out of hand, because it’ll undermine the teacher’s confidence and confuse the pupils, who will see you as the one in charge.

Look friendly and happy. Say something positive to the teacher as you leave the class but if things were dire at least be empathetic :’“You have the patience of a saint”, or “understanding fractions is really hard”.

After the lesson, give yourself some time to think about the teaching and learning you’ve seen, focusing on strengths, what has got better and one or two areas for development. Don’t fall into the trap of discussing the lesson straight away.

Don’t “feedback”, that is, doing all the talking while the teacher listens passively. Aim for them to do most of the talking and thinking. People develop by coming to solutions themselves rather than being told what to do or criticised, so encourage reflection by asking open-ended questions, such as, How do you think the lesson went?; What were you most pleased with?; Why?; If you taught that lesson again, would you do anything differently?

Be clear about your main message and convey it to the teacher. Don’t raise every small thing that could have been better: there’s no such thing as a perfect lesson. Remember, it should be useful to the teacher.

Don’t talk about yourself or other teachers. Comments such as, “I wouldn’t have done that”, or “I would have... ” will probably irritate and alienate.

Be aware of your body language and notice the teacher’s. Be sensitive to how the teacher is feeling and ease off if necessary: Rome wasn’t built in a day.

And finally, ask whether the observations you do are helpful.

Sara Bubb (s.bubb@ioe.ac.uk) runs courses on observation. Her new book, Helping Teachers Develop, is published by SagePaul Chapman and can be ordered through The TES bookshop (pound;15.99)