Just as it is with most things in life, preparation is key. I would advice everyone who is thinking of participating in an IDC and becoming an instructor to do research and find a diveshop that is right for you. Even though the standards set by Padi are the same for every IDC, every Course director and diveshop is different. So do some research, and find the one that feels right for you.
When you have found a Course Director you are comfortable with, you want to prepare the best you can before the start of the IDC itself. We use e-learning here, which means that you can finish with all the dive theory before day 1 of the IDC. This way you can put all your focus on the different workshops you need to attend. After a long day of workshops and teaching presentations you want to relax and not spend the whole evening studying up for the exams.
With the dive theory out of the way, you can focus more on your own dive skills. Another part if the IDC is the skill cirquit. You need to be able to demonstrate all the skills. Even if it sounds cliche: practise makes perfect. On our divedivision youtube page we have recorded all the 24 skills you need to master:
https://www.youtube.com/@divedivision7255
And finally, the last piece of advice I can give you is to enjoy it! Even though the IDC can be stressfull, dont forget why we dive: it's funn!