The best way to be prepared is honestly to do your work. Every assignment for every class. However, to do each assignment well, you have to be prepared for the content. That means reading prior to class, taking notes and engaging when possible doing class, and reviewing information after class. This takes more time and effort that you probably are accustomed to, but it's not impossible.
Go back to your time management plan and be honest with yourself about how well you've stuck to it, in general. I mentioned in previous posts and episodes that your time management plan is a guideline, not set in stone, and it is intended to provide a general idea of how to structure your time. However, using it helps. Using your time wisely helps, as well.
So if you aren't where you want to be with any (or all) of our courses, do something differently. Switch up your study space. Try to study when you're most alert. Read more or differently. (Side note: Try SQ4R if reading comprehension is a challenge.) Do more problems. Go to office hours one more time per week. Do all you can to create a different outcome. This is particularly true for anyone who is relying on high school habits and hoping they will work out. And if you are where you want to be, keep on doing what you're doing. And perhaps reach out to a friend who isn't doing as well and bring them along with you. No one gets though college alone.
Whether you are leading, following, or collaborating, you can make it work.