Scanning letter by letter
The Sudoku singles, done with letters.
Pick one letter, say B, and look at each box that is still missing it. Rows and columns that already hold a B rule out cells in that box. When only one cell is left, that is where B goes.
Then look the other way: pick an empty cell and check its row, column and box. If eight different letters are already there, the ninth is the answer.
Saying the letters out loud, or thinking of the word they spell, makes it easier to notice the missing one.
Practise it
The Hint button on every puzzle explains the next step in the same plain language, so you can learn as you play. Play a Wordoku puzzle.