If you're going to teach a sentence, you have to abstract it a little. Maria parvum agnum habuit is a great sentence, but you'd be hard pressed to build a whole lesson on that one line Instead, you want to think of the sentence you're teaching more in terms of its form. The form here is [subject] [adjective] [object] [verbed].
To teach that sentence, you're gonna have to repeat it a lot. How you do that is up to you. I've seen different methods; I like storytelling, myself. Regardless of how, though, you'll need different variations on that sentence.
You can vary it a lot of ways. Here's a few:
Let's do this sentence as a story.
And so on. Note how you can change any part of the sentence and retain the basic structure. Gives your sentence room to breath. I went for minimal verb changes, but you can swap out any part of the sentence.
You can use variations to teach specific concepts, if you like. Suppose you want to teach some tense variations.
You can squeeze a lot out of just that one sentence. It's got a subject, which can be singular or plural, and any of five declensions, as well as an object and adjective with the same possible variations, plus the possibility of cross-declension case agreement. It has a verb with a tense and an aspect and a person, any of which could be targeted for the lesson. You could teach a significant chunk of the Latin language just by varying that one sentence.