@jennythelib - As a middle school English teacher, I haven't done DGP myself, but I've heard good things about. You're right that there needs to be a little more to it than writing, but of course the problem is that the sentences in workbooks and so on are so artificial that it doesn't really help students discuss it in the real word.
What I shoot for is basically teaching grammar in context. I was inspired by a book called Mechanically Inclined by Jeff Anderson, which talks about how to introduce some fairly technical grammar concepts through "mentor texts" - real-world sentences. Students will look for their own example sentences in their own reading and you help them learn through discovery.