First of all. Everyone has their own approach, it's all individual, and my way might not work for others. You need to find your own source of imagination and inspiration, but I hope my methods will point you in the right direction.

Of course its Top 1 and the most important!
I love drawing since childhood, drawing every day at home and school, and everywhere, and still do it to this days. I take my tablet or smartphone and pen, go for a walk/way to work/on playground with my kids, and draw something, it could be something i see, or tasks and sketches for personal projects i have in mind. Back when I didn’t have a tablet, I bought a pen for my phone, downloaded Procreate, and went outside. I’d find an interesting spot, take a photo, and try to draw a concrete sphere into the scene, adding all the light and shadows falling on it, that cool technic i saw in awesome painting artist Marco Bucci (https://www.youtube.com/@marcobucci). This trained my eye to see color and light, understand where light and shadow fall, reflections, global illumination, etc. And be able to compose my CG to footages better. Also there is cool technic is from great concept artist Jama Jurabaev, to draw black-and-white concepts, limiting yourself to 2-3 shades of black and gray, and try to create cool concept like this. Then you can add gradients and work on multiple ideas to expand your imagination and see what you can create. There are tons of such lessons online nowadays—just be willing to search, and you'll find resources suited to your needs and skill level.

Take a photo of everything!
I enjoy walking with a camera during my free time (no need to have a good camera, its just an excuse, sometimes i go with smartphone), searching for interesting angles in ordinary places. It’s about training your eye to see the extraordinary in the ordinary and finding unusual compositions. This is a valuable skill—walking into your backyard, which might feel dull after years, and discovering angles and compositions you’ve never noticed before or creating them yourself. My Achilles' heel is bokeh—I focus exclusively on it, often shooting evening or nighttime scenes to capture colorful and varied bokeh effects.
Lately, I’ve switched to street photography, capturing people and portraits. I’ve never been fond of this, but I’m a fan of experiments, so I decided to give it a try. My inner introvert strongly resists, but I force myself to step out of my comfort zone, often making eye contact with people and seeing their disapproving looks, like, "Why are you photographing me? What the heck?" I’ve taken thousands of such shots, and so far, no one has approached me or broken my nose—there’s still time for that!
Anyway this also train you eye to see materials and lights around, finding good camera angle and composition, how lights and color works and how to use it on CG. But it all takes time and better if you try to replicate it in CG and test it.

Play music everywhere and always in you mind!
I play some music instruments, piano, guitar, drums, accordion and sing. I used to write songs and music in FruityLoops and Ableton. This is for the soul and to take a break and switch to another activity, which helps refresh the mind. And get emotional refill. For you work it helps like developing of your rhythm sense, which is helpful in video editing, motion design, where you need to always create super dynamic motion that synchronizes to music and sound you find. It’s valuable for everyone, sooner or later, we all make short clips, reels, etc., where music, sound, and editing matter. Developing a basic musical sense can help you avoid putting awful soundtracks in your reels that make people’s ears bleed, which i see a lot and its awful.

Do something not related to art at all to refresh you mind and get rest!
While sports themselves don’t directly enhance creativity, I’ve noticed that when I go for a brisk walk, take an hour-long stroll, or practice yoga—without music or, at most, with chill ambient sounds that don’t distract—it sparks good ideas in my mind. This is important! Physical activity gets the blood flowing, engages the brain, and thoughts start to accelerate. Sure, there are many unnecessary thoughts to push aside, but overall, this often yields plenty of ideas, which I quickly jot down to avoid forgetting. Also its refreshing you mind from many hours of working and starting to hate what you do.
Do whatever you like, dancing, joggling, cycling, swimming, tennis, boxing, anything you have fun with and that make you feel free and forget about art for 1-2 hours at least and you get that refreshing im talking about after which you would love to came back to your art work with fresh mind and see problems clearly or new ideas!
Try everything, experiment, except drugs of course!
These are just my experiences and methods. Find your own ways, try different things, and experiment. The key is to force yourself out of your comfort zone—get off the couch, put down your phone, and make the most of the tools at hand to push your brain to its limits. Watch tutorials, Google how things are done—we live in the internet age where everything is available. Don’t know where to start? Just Google it, use ChatGPT!
“How to start drawing from scratch”
“How to start photographing with a phone from scratch”
“Basic principles and tips for street photography with a phone”
Or even something as simple as “How to develop creative skills.”
So, let’s get to it!
Feel free to share your own methods.
P.S. This is a very brief summary. I plan to write a long-read with examples, tutorials, and links for each category if anyone’s interested.