How we change what others think, feel, believe and do
Be clear and exact in what you say, such that the students can easily understand what you mean and what you want them to do.
When giving instruction, say what you want them to do, and maybe what you do not want them to do. If they are doing something and you want them to do something else, say 'stop that and do this' (naming what that and this is).
When explaining, do so not for the brightest but so that as many as possible will understand. Any who do not understand a full and clear description will need personal attention.
Please get out the copies of Tom Sawyer that I gave you last week and turn to page 32. Michael, can you start reading aloud from the second paragraph, starting 'Tom said' and continue until I tell you to stop.
It is always remarkable how some people can misunderstand something you say, and you may indeed be forgiven for wondering if it might be deliberate. Of course it sometimes is, and preciseness in instruction can help avoid such fogging games.
It is also true that when one person says something and thinks they are clear, then many other quite reasonable people will not get the full meaning as intended.
Breaking the instruction down into individual actions helps them know exactly what you want.
A simple test of clarity is the 'Granny test', of being so clear even your grandmother would understand (though perhaps this is a bit unfair on grannies).
By being precise, you will teach the children to also be precise and thereby think with a clarity that will serve them well in the rest of their studies and life.