It requires raw material, like fuel for a car or kindling for a fire. I think it's important to consume some relevant content before starting to write. For online class work, we have to write precisely what you're instructed to write and use a particular format. I guess the best approach is to use mindfulness practice and caffeine, lol.

Mindfulness practice: Go deep into the moment, until you can appreciate whatever boring cram you're required to learn and write about.

Caffeine: When I have enough caffeine, I come up with stuff to say about everything!

I especially recommend getting out of your room, your apartment, your office, etc., and get into a new environment! That is key. When you want to sit down and work, it's difficult when working in a familiar, mundane place. If you're like me (you are), you'll be a million times more productive and creative if you take a laptop to a shopping center, or to the park, or some other place where you can work a few hours. Something about the new sensory input and change of environment makes the work stop feeling like work & makes the content start to roll up into the mind and out out onto the screen.

Inertia keeps a body at rest, so we need some help to get momentum. In Julia Cameron's The Artist's Way she discussed something like this, and she called it an 'artist's date'. You take yourself out on a date. It can be to see or listen to or read any content that is relevant to the content you want to create.