Dont sweat it, finding your own style for lesson plans and feeling confident that you're approaching them correctly is one of the harder parts of getting started with your CFI preparation.
Remember the purpose is to serve as a map for your teaching, not to be an article the student will read. Dont make it a narrative, just lay it out as a reminder of things you will teach.
The natural structure is an outline. Use the sample lesson plans in the AIH and go from there.
Define your objective, what is the student supposed to take away? If it's their first lesson on a maneuver, you probably dont care about PTS standards, you want them to focus on fundamental understanding and aircraft control... so set your objectives respective to the circumstances and where this student is at in their learning.
Next step is figure out how to explain to the student why they care, why are they learning this. A quick anecdote, "man this one time I got stuck on a cross country because....". Or later on, when you're less likely to scare a new student you can occasionally bring up some accident reports that illustrate a point. Things like that... dont just dive into dry technical knowledge without setting the stage for "why we care".
Then what are the major areas you'll cover so that the student has a good exposure to this big idea. Then under each of these major areas, create bullet points for each key point and illustration you'll use.
As for homework, I keep it simple... small bite-sized things that will help them be prepared for the next lesson and/or remember what they did on the last lesson. A pile of assigned reading and work is just not going to happen for 90% of students unless you're instructing at a pilot mill/university.
Some example homework I give:
I'll let the student know what we are going to do next and direct them to the relevant section of the Airplane Flying Handbook or some other resource... "Hey browse through the info on rectangular courses, turns about a point, and s-turns in the AFH, chapter 6... that's what we'll be doing on your next lesson".
I might email 2-3 youtube videos of bad landings and ask them to email me back with their ideas about what went wrong, how they can prevent that from happening, and what the correct recovery is when they find themselves in that situation.
For students just learning traffic pattern work, I'll get them a copy of a checklist and I've got a cockpit poster of my trainer I made and tell them to work through the taekoff, downwind, abeam, base, final, and landing in their head, touching controls and thinking about what instruments will be indicating. Or they can do this in flight sim. It helps them get the procedures down so that when we really do fly they can focus on flying the airplane instead of remembering where the carb heat knob is.
Finally, ground/knowledge-area lesson plans tend to be much bigger (mine run 3-6 pages for a 30-45 minute lesson) because there's more knowledge to convey, while flight lesson plans should really fit on a 5.5 x 8.5 sheet of paper (letter stock folded in half)