My time-management is so poor that I don't even have the time to write a schedule for time-management. ;-;
This may work like a debt, where you need more income to pay the debt but because the debt has interest you have less income ... if you just didn't have any debts, you could afford to pay off your debts! :/
The trick here is you don't actually need a time management plan. You just ned to get your shit back on track and people will stop complaining. You need to use the most expedient method to get there. Filling in a form or writing a paper on how you are going to spend your time is not the answer.
I'd suggest just buying a little pocket day planner and writing down all the things you have due, with an entry on the actual due date and an entry exactly one week earlier. Anything in the past, find out if you will get any credit at all for doing it (if it's at work, make sure nobody else did it already out of desperation from waiting for you to finish). If it doesn't get you ahead, strike it out. Anything left from the past is probably only worth partial credit - which means it doesn't matter whether you get it done today or next week. Which means you need to focus on imminently upcoming due dates so they don't slip into late partial credit territory. Better to disappoint one person for two weeks than disappoint two people for one each.
So far we're just at a trip to the store for the planner, a look through your notes or syllabi, and writing in due dates. You should be able to tackle this in an hour or two.
Now we come to the actual time management part. Every thing you do in your life is separated into "Must do to survive", "Must do to succeed", and "Desire to do to be happy". I agree that happiness is a contributing factor to success, but spending time playing video games when you have projects due tomorrow is a poor choice - in exchange for extra happiness and a tiny boost to success, you miss out on a huge boost to success you could have by doing your work.
You need maybe 4 hours of sleep to survive, 7 to succeed (because you have enough sleep to learn and do well on your work), maybe 9 to be happy in the morning. That's two hours you can easily shave off of your schedule, making you less happy, but retaining most of your ability to succeed.
After your basic success needs are met - enough sleep, travel time and class attendance - you have the success needs that you might not consider to be needs but really are. If you have a project to do, and it's due next week, why wait? Just get that shit done. Get it done before you pursue a leisure activity. Prioritize your to-do list over your leisure time. Maybe a friend says "come down to the quarry with us and shoot off fireworks and drink from tiny liquor bottles" but you have to turn them down because you actually have responsibilities and you need to fulfill them.
At all times you will find that you can pursue leisure with all of your time without getting enough of it. If you ire of video games you can go for a run. When you've had enough sun you can lie in the shade and read. If you choose leisure before work until you have had enough, you will never get to your work. In short, if you have work that you
can do, you
must do it, before your leisure.
There will be times when you have a project due in the future but you don't have the resources to complete it. You start, do as much as you can, and hit a wall. It's unreasonable to expect that you can do the last piece of work in a class at the start of the quarter / semester: if you could do that, why are you taking the class? So it's fine if you have some work due next week but you can't do it yet. But you're responsible for getting started and doing as much as you can with the resources you have every night. It's not ok to get the project assignment, do 1 page out of 5, then leave it until the night before it's due.
In choosing which tasks to work on, and especially in catching up, I suggest placing deliverables before reading in importance. I know you need the reading to understand how to do the deliverables, but you will not be graded on your reading. You will be graded on your papers and tests. Do what you need to get those in, and with your spare work time catch up on your reading. Likewise if you have two pieces of work to do but you can only possibly finish one, o the work that will have the greatest impact on your grades. Let's say one piece is worth 1% of your grade and the other is worth 4% - do the more valuable piece. But if you're failing in the 1% piece's class, and doing well in the 4% piece's class, choose the 1% because you have a lower class grade to bump up. This should be pretty obvious to you in practice - do the work for your worst class before doing work for your best class.
I could shower for an hour in the morning, because I love scorching hot water. But I've figured out that (a) my girlfriend wants some water too, so I need to cut my showers shorter, and (b) I value an extra half-hour of sleep more than I value an extra half hour of showering. Similarly, look at what you do with your leisure time and figure out what does what: does watching Youtube LPs do something different for you than painting? Don't waste time doing leisure that you don't need at the moment, figure out your mood and actively choose a leisure type that will fulfill you.
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Eventually you will dig yourself out of your work backlog, scraping up a few measly points for turning in late work. You'll be caught up, and turning in new work on time and then ahead of schedule. You'll be tempted to skip all the old reading - go back and buckle down and just do it! And in the future you'll be tempted to let your good habits slide because everything is fine now. But if you don't keep up with these good habits you'll be right back where you started.
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TL;DR: Get a day planner. Write down your due dates. Get
all of your work done before you play.