How do you all design your factories?

I’m a new player and Every factory I have right now is just a box of sorts with windows put in. How do you guys plan your factories? Do you get real life inspiration or does it just come naturally to you all? Any design tips and or resources would be greatly appreciated!

Edit: Just wanna say thanks for all the responses! You guys have given me a lot of great information to go through! One thing for sure, I have a lot to learn before I can even begin to think about making stuff look nice! Thank you all!