For true beginners, check if the student knows words from these categories:
Mention in the description if they need to work on those words and how you know. (Example, “Johnny knows 2 color names, red and blue, but could not name any other colors. He needs to know these words…”
List any additional words you had to teach in the lesson.
If the student is advanced, quiz them on some words' definitions. If a fluent speaker can use the word but cannot define what it means, this can be a goal of theirs.