Students are guided in learning how to be still.
Preparing the Room
In order to get maximum benefit from using visualisation pupils need to be in a relatively quiet environment where they will not be disturbed. It is not necessary to be silent, (an unrealistic expectation in a school!) but it may be a good idea to choose your time slot carefully, avoiding noisy times of day. Check the timetable to make sure it does not coincide with the class next door doing Music for example. A 'Do Not Disturb' sign for the door is advisable (you could choose a child to write this) and try to secure at least ten minutes of uninterrupted time allowing the pupils to really enter the zone.
Preparing your pupils
Posture and breathing also determine how effective the exercise will be. Before the visualisation, ask pupils to sit upright, with both feet on the ground in a state of mind best described as 'alert and relaxed'. The body shouldn't be slouched, and relaxed doesn't equate to feeling sleepy. Sittling upright with a straight back, relaxed shoulders and breathing deeply from the core, assumes the right posture for focused mental intent, bringing the body under control. Encourage pupils to breathe from their stomach rather than their chest, maybe placing a hand over the abdomen to begin so they feel the gentle rise and fall of breath during deep relaxed breathing. I have added a Stilling audio file for your convenience, but again, don't feel obliged to use it, if you would prefer to lead this yourself. With practise it will become an automatic habit, and you will be able to get the class into a calm relaxed state very quickly with a few simple verbal prompts.