Thank you for the tip pages!
I'm not sure if I've just been missing them all this time, but having started on the iOS version of Duolingo, I went through the first two units without seeing the tip pages. Reading them today has been a revelation and answered a ton of lingering questions. They're really well structured, and the examples make the concepts very clear, so my huge thanks to the author(s).
The tips and notes are only available on desktop. It's frustrating for us that so many users don't have access, and a delight to read your post and know that someone is discovering them. It would be pretty hard to figure out what Klingon is doing without some kind of coaching.
The lack of tips pages did have the benefit of helping me establish good habits early on; but yeah, at least as the course is currently structured, my frustration quotient started rising rapidly around the introduction of imperatives. I doubt I'd have made it too far through the third unit had I not been driven to the desktop version and found the tips pages.
It would be a matter of making sure each lesson introduced something new, but not too much.
For instance, if by lesson N you've learned how OVS works, in lesson N+1 you can learn how to add locatives to the beginning. Each lesson would introduce a single grammatical concept, plus new vocabulary.
I think it would also help if the lesson wasn't trying to "make a point" about grammar by forcing odd address and multi-sentence examples (e.g., yIQong, torgh to force a yI- prefix instead of a pe- prefix, or Do you see them? Yes, we see them bolegh'a'? HISlaH, DIlegh to force the unspecified object to be plural.
I've listened to some of the Vialingo Klingon lessons, and they follow this kind of step-by-step progression very effectively. Sure, you start with extremely basic sentences like jIQong and bIqet, but each lesson builds on the previous one piece of grammar at a time. Pretty soon you're saying things like naDev loSqangbe' HoD QuchHa' The unhappy captain is not willing to wait here and mebpa'mey retlhDaq Sor tu'lu' 'ach vItoSlaHbe' There is a tree next to the hotel but I can't climb it. I really think you could get to this level in a handful of lessons, quick enough to avoid boredom. Then, you can take your time introducing each new syntactic noun and verb suffix in tack-on phrases, as well as gradually add the more obscure verb prefixes.
The Klingon Duolingo second lesson, in contrast, starts with sentences like jIqet 'ej jISup and maqet 'ej SuSup and presents them in various English tenses. That's too much for the second lesson, where the first was just stock phrases to memorize.