I don't consider myself an expert at this, but there are one or two lessons I can definitely jot down on how one should study (or "lock in" for frenzies).

Rule 1: Focus on a single task for hours. I had this weird habit of dividing my free time to finish multiple tasks. I thought I was being productive. But I was just being performative. I can't cite any study to back this up, but the real "lock-in" doesn't start when you start. It starts when you are deep into the task, surfing on the flow. Switching the work after "locking in" for 40 minutes is counterproductive. And yes, I will be bold and say the Pomodoro or anything alike is borderline bullshit. You can't reach the flow state when you keep switching.

Rule 2: Don't choose places. A student who can study at home can also study at a cafe, or a library, or a fast food place, and even that sturdy bench in the streets (happened). If you think you can only study if you go to a cafe, then reconsider. Reconsider if you can actually study. And reconsider whatever you call "studying" is actually studying. You are only losing time if you are stuck between options. Kierkegaard was a pessimist. A better quote would be: "do it or not do it, time will pass anyway." (A personal preference, but home is the best. Not a big fan of losing my valuable hours commuting).

Rule 3: Invest in a great chair. Comfort is a huge thing if you want to lock in. Yes, I was overstating with that bench thing in the previous paragraph. Your body needs to feel right. Don't leave any ounce of discomfort. Mind and Body are connected. They influence each other. You can't finish that paper while lying down or with a spine bent in an oval form. Good chairs are expensive. But the return on investment will be high. Higher than investing in Bitcoin back in 2013.

Rule 4: Fix your sleep schedule. Mornings are the best time to study. Make it a habit of yours to sleep early and wake up early. You will feel happier. Fewer headaches. And those 24 hours finally seem like 24 hours. And if possible, have a 10 minute walk to start the day. That 7am sun is like a recharge.