Studying with unmedicated ADHD isn't a willpower problem. It's a brain-wiring problem. Your brain is built for a sprint, not a marathon. It wants new things and gets crushed by boredom. So the usual advice to "just focus" is worse than useless. You need a different approach.
The real enemy is the giant, undefined task. "Study for finals" is so big it's paralyzing, and your brain will look for any escape. You have to break it down into ridiculously small pieces. Don't "study chapter 4." Your goal is to "read the first two paragraphs of page 87 and highlight one sentence." That's it. Do that, and then walk away for a minute. Feeling good about finishing one tiny thing is the only fuel that gets you to the next tiny thing.
Time Isn't Real, But Timers Are
If you have ADHD, you probably have time blindness. An hour can feel like five minutes, or a minute can feel like an hour. That's how "I'll just study for a bit" becomes a three-hour Wikipedia dive that starts with Napoleon and ends on the history of the spork.
So you have to use external timers. Aggressively.
The Pomodoro Technique is famous because it works: 25 minutes of focus, 5-minute break. After four rounds, you take a longer break. This isn't just about rest; it creates a rhythm for your brain to follow, giving you the structure your internal clock can't. You can use an app to manage these sessions and set reminders so you don't forget to start in the first place.
My friend in college swore by this. He'd set a 20-minute timer with the only goal of keeping his pen moving—doodling, outlining, whatever. It didn't have to be productive, but it kept him at his desk. I remember walking into his room at 4:17 PM one Tuesday and he was just furiously drawing cubes. Ten minutes later, he was deep into his chemistry homework. He tricked his brain into getting started.