A neat way of counting the suit you’re attacking is with the subtractionbytwo method. Follow these steps for successful counting every time:

Count how many cards you and the dummy have in the suit.

Subtract the number of cards you and dummy have from 13 (the number of cards in a suit) to get the total number of cards your opponents have in that suit.

Each time you lead the suit and both opponents follow suit, subtract two from the number of cards your opponents have left.
When your opponents have no cards left, all your remaining small cards are winning tricks.
You may discover an easier way of counting, but for most people the subtractionbytwo method works just fine. If you just have to be different, here are a couple of other methods:

The digital (fingers and toes) method: This method requires playing with openair sandals so you can see your digits clearly. Not ideal if your host likes to keep their home on the chilly side.

The fakingacount method: You look intently at the cards that have been played as if you’re counting them. Then you look up at the ceiling as if you can see the count up there, and finally, you nod sagely even though you don’t have the vaguest idea of how many cards your opponents have left.