When I wanted to become a teacher, I had no concept of trying to make lessons. I don't know what I thought happened, but I figured this must be some magically ability bestowed along with your teaching certificate. The idea of planning activities for classes was completely foreign to me. My ideal teaching experience in my head contained a lot of class discussion and generally looked more like a cool coffee house chat than what I know about lessons today.
Now that I'm a real, live teacher, lesson planning seems very second nature to me. While student teaching, I was described as having a then hot made up phrase called "with-it-ness". It means the ability to change your plans on the fly. Give me thirty kids and seventy minutes and I can almost guarantee that I'll be able to keep them from ripping each other to shreds. Three years ago? Not so much. Half of lesson planning is about understanding timing and realistic expectations. The other half is always, always, always having a back up!
My lessons come from a variety of sources. My first go to is what I like to call The Bible. The Bible consists of the lesson plans developed by the district. I call it The Bible not because of its usefulness, because the lessons can be too short or not relevant to my students, but because it's freaking huge. All of the district units take up several large binders. I generally pull resources, like articles, monologues and short stories, from The Bible. Some of the lesson plans work out, or work well with a little tweaking. Others? Well, they might work in someone's classroom, but not mine, and not with seventy minutes to fill instead of fifty.
The best place to look for lesson plans is your coworkers. One of the things I love about my school is that we work together really, really well. It's easy to be a first year teacher at my school. Some of the veteran teachers (not old, veteran), would literally just hand me stacks of resources and lesson ideas. I still go next door to my neighbor and ask her about lesson plan ideas. Some of my best lesson plans are updated plans from the last decade. There's nothing wrong with using "old material". It worked in the past for a reason; it's good.
I do build my own lesson plans. It's much easier now that I have a couple of years under my belt and a huge amount of resources built up. My lesson ideas come to me when my brain goes blank, like when I'm running. One coworker wakes up in the middle of the night with lesson plan ideas, so she keeps a pen and paper by her bed.
The first lesson I ever planned was atrocious. It was about diagramming sentences. Seriously. It was awful. I've looked over it since becoming a teacher. I planned it for a 90 minute lesson (block scheduling instead of the current trimester schedule). If the entire thing took more than twenty minutes, I'd be shocked. But hey! I was young and ridiculously unexperienced. Now I realize why my then professor just smiled and nodded along as I told her about this awesome lesson plan I made.
Of course, like everything else in teaching, you need to be prepared for the best laid plans to be absolutely ruined. What's that? You have an awesome lesson planned tomorrow? Oops! Tornado Warning! Now you got through twenty minutes of class before having to sit in the hallway for the remainder of the period. Your week is now shot and you have to fix it. Relax. It happens. Stressing out over the perfect unit is ridiculous and unnecessary. It might not be freak weather messing up your perfect plans. Your kids? They might not get the concept after your lesson on Tuesday. Guess what you're doing Wednesday now!
Lesson planning can be really easy. You just have to learn to roll with the punches and keep adapting things for your students. After all, I may have taught the exact same units for three years now, but I always teach it differently. Why? Because my kids are always different.