Many years ago there was a question about how you plan. To force better diligence on my part, I had developed this system that involved a couple notebooks and a big calendar.
Towards the end of last year, I finally scrapped this sytem after five years. Why? Primarily because I'd worked through the issues that forced me to it in the first place. Namely, learning how to script my time, remember finer details, and getting good at my content. As it stands now, planning a decent 50 minutes isn't as hard as it used to be. In some conversations with people while out and about at conferences, you just accidentally become really good at planning.
This year I went all digital. A 12.9" iPad Pro took the place of the paper.
My planning has three elements: scheduling, formal write up, and product list. I use Notability on the iPad and the built-in system Notes app on my computer and iPad. Notability is set to back up all my notes to Dropbox so I can view them on the computer if necessary, and the Notes app auto-syncs between iPad, computer, and phone.
Previously, I'd use a paper calendar to make broad strokes about what I wanted to cover on a day. The calendar was marked with holidays and grade entry dates to help me plot out assessments in a reasonable manner. Then I'd take a notebook and script out each day of the week. Now with the ability to super zoom in on the iPad I can wrap both of these tasks into the calendar. Each day has the script written with different color codes for assessment (red), homework (blue), and classwork (purple). If I forget something, thanks to the Dropbox back end, I can pull it up on my phone for a reminder before class starts. I do this super frequently. Previously I'd do the same thing with my script notebook nearby.
Once I have the week planned, I scan the scripts for assignments I need to make. Am I assessing? Need to make that. Am I giving classwork? Should check to see if a previous one works or if I should edit it (which, when you have two weeks off for a hurricane, the answer so far is "LOL, yes you have to edit it"). Something something Desmos? Probably should figure that out.
I keep the "to make" list separate from the "to do" list as that includes other random parts of the job (answer this email, order this thing, sign up for this thing, etc).
After all that's figured out, I write up formal lessons for documentation. I keep these in a Google Doc that are shared with my department chair and appraiser. Objectives, language goals, and a brief run down go here.
I have really liked this system because it forces me to go through the week a few times while planning, better committing those plans to memory. I've passed most of the content hurdles now, so I don't have to keep as many detailed notes about how to cover a topic.
I use plans from previous years as reference, but I never blindly copy and paste. Often I'm able to reuse passed assignments with minimal efforts, but each year is different that they usually deserve something unique for the moment. As it was described to me a long time ago, if you force yourself to throw everything away and start over, you will become really good at your subject matter, really fast.
And finally, other than plotting some assessment dates in advance, I never plan out beyond a week. There's too much uncertainty in a given week. Things might need to push. Something might go faster than planned. You might have a better idea by Wednesday. Making a semester's worth of copies doesn't happen around here.