"Handing out a worksheet" and "teaching with a worksheet" are two very different things. The first means heads down, a quiet room and a breather for the teacher. The second tells the teacher exactly where each child is stuck. Same sheet of paper, worlds apart in what it gives you, and the difference comes down to these four things.
1. The Worksheet Comes After the Teaching, Never Instead of It
A worksheet is where children "use" what they have just learned, not where they "guess" at what they haven't. If half the class can't do it, the problem is neither the children nor the sheet. It's the order. Go back, teach the part they are stuck on, then hand it out again. A worksheet nobody can do teaches one lesson only: that English is hard.
2. The Instructions Have to Make Sense Without Asking the Teacher
The biggest single loss of time in a lesson is the "Teacher, what do I do?" stretch. A worksheet for Grades 1 to 3 wants short instructions and a worked first example. Add the instruction in Thai underneath and the class can start on its own inside thirty seconds. That buys you the time to sit beside the children who genuinely need you.
3. The Answer Key Is the Teacher's Tool, Not the Child's Shortcut
With no answer key, the teacher marks every sheet and every item alone, and the feedback reaches the child a day late or worse. Learning happens when a child sees where they went wrong, and "straight away" is the part that matters. A separate key, ready to use, opens up techniques like swapping sheets to mark each other's work, or pinning the key up at the front so children who finish early can get up and check their own.
4. Repeat the Topic, But Never the Same Sheet
A set of words needs five to seven encounters before it settles into long term memory. Hand out the same sheet again, though, and children memorise "where the answers go" instead of the vocabulary. One topic wants several worksheets that ask different things: picture matching in the first, gap filling in the second, using the words in sentences in the third. Then the memory gets pulled out from a new angle every time.
That is why our worksheets come three to a topic. One choice plans three lessons.