You might want to make a list of keywords before you start writing. This will help you standardize spelling. For example, suppose you are making an art Cycourse, and you make up keywords as you go along. You might type the keyword “Colors” on one page, “Color” on another, and “Colours” on a third. That creates three different items in the keyword list. It would be better if you decided on one keyword – maybe “Colors” – before you start writing.
Of course, your initial keyword list won’t be complete. You can always add to it as you go.