I don’t have OCD, but this is something I have struggled with too. I think everyone who visits this site struggles with this, as it goes with ADHD. A lot of the problem is, if you don’t get a diagnosis as a child and are taught coping strategies, it can be hard to learn how as an older child/teen or adult these strategies retroactively.
First off, find out which kind of procrastinator you are, as linked a couple posts above. If you are the type that seems most common (chicken), then a lot of it is being overwhelmed. If you fall under perfectionist, you can still get overwhelmed.
Second, learn to change the way you think. You need to realize that you don’t need to work on your whole thesis, but write a sentence. A lot of the problem is just getting started. Also, you need to realize that you are not perfect. That is ok. When I need to do laundry, I started thinking of just sorting it real fast, pick my most urgent load, and put in washer, THEN put that in dryer and start my second most urgent load, etc. Saying you’re going to start a load of laundry is less daunting.
Third, learn to develop a system of organization. Many ADHD people will swear that the Bullet Journal is a great system. I have been working on using it and even though I’m not proficiently using it 24/7, I do use it more than not. It has taken me a couple months to get this far, but I have already gone from being unproductive to getting more done. Some people prefer digital systems, and I do use it for reminders: “Hey Siri, remind me I have a therapy appointment tomorrow at 7:30 in the morning.” Boom, done. I remembered my therapy appointment on a Monday morning at 8!
Forth, get some help. I love to occasionally read Mark Manson’s site. He has a lot of good free content, and his perspectives have given me a big help. One article is https://markmanson.net/goals. There are a few more. He is crude, but honestly he puts things in a way that hit me. Also, I started seeing a therapist. If you don’t know much about psychology, a therapist may be a great option if you have access to one.
Fifth, change is small. One thing I read on Mark Manson’s site is that we don’t change that fast. We are like the Titanic trying to avoid the iceberg, and the rate of full turn is not enough to avoid it. But that proves a point: we are creatures of habit.
Six, start small, and start early. We have an attention budget (queue mindfulness and pomodoro timers here), and it is full in the morning. Also, starting small things will lead to bigger things. Every morning, make your bed. Every morning, take a 5 minute walk around your block or up and down the street before you get in the car. Every morning, take five minutes, stop and enjoy your coffee in the quiet.
Seven, change the mental script. It takes 5 compliments to outweigh 1 negative comment. This applies to ourself. We are our biggest enemy. You have ADHD, you are not ADHD. You have procastinative habits, you are not a procrastinator. Get that tone out of your head. You will still be procrastinate in a year; heck, even neurotypical people procrastinate to some point. Once you take emotion out of your tasks, they don’t seem so daunting. Realize that your best work will happen probably in the first draft, not in the fifth.
ADHD people tend to put their best work due to higher creativity in the first attempt. For example I used to practice public speaking 30-50 times, but I eventually realized a stupidly simple outline plus two practice sessions was all I needed and it sounded great.
Eight, take time everyday to look at your calendar/to-do lists. Also, take time at the beginning of the week to do so. Most neuro-typical people do this or realize they need to do this automatically.
Nine, just do something sloppy. It’s better to do something sloppy and start a week or two ahead of the due date versus the night before. A C is better than a F.
Ten, set the bar at zero, not 100. If you have no expectations, you can’t be disappointed. Yes, you’re still responsible for your own actions, but not expecting great actions but terrible actions will lead you to get your brain out of it’s own way.
Eleven, get help. Whether it’s a friend who can just slap you in the face, a therapist, a tutor, ADHD coach (highly recommend!), or a support group, GET HELP!