While I'm a strong believer in the idea that people are more likely to discount their ideas so quickly that they don't even recognize the fact that they crossed their minds, sometimes we definitely need some help pulling them out of us. Recently I held a "Promptathon" event for the Drawabox community - basically a new prompt each day, with each one being detailed but open-ended, allowing participants to stick as closely as they like to it, or take it way off in their own direction. As a result, we have a bunch of such prompts which you can find here: https://drawabox.com/drawingprompts/random Perhaps these kinds of prompts will help you get started as a jumping off point, until you feel more comfortable doing so on your own.

That reminds me of something Feng Zhu talked about in some of his YouTube videos a long time ago - creating a world that is just different for the sake of being different, rather than using the real world as a grounding for our ideas. The farther we stray from reality, the harder it becomes to make a particular design direction plausible to the viewer. Above all else, our responsibility is to solve a given problem while maintaining the viewer's suspension of disbelief - their willingness to set aside the obvious issues with the idea and just accept, "this is the way it is". That said, it's also really difficult to think of ideas that are so far out there that they're impossible to solve. Feng Zhu's example was, if I remember correctly, something like a world made of cotton candy or bubble gum or something - but the very fact that these are materials with physical qualities we can understand, things we've probably touched before, means that while they are challenging to bring into the realm of plausibility, they're not impossible. Similarly, the concept of needing to charge a cellphone is a relatable, familiar thing. Sure, in this world we'll use maize grains to give it juice, but who's to say we don't throw a bunch of corn into the charger, and that it undergoes a chemical reaction to produce a charge? We can do it with potatoes after all. Potatoes may not produce too much of a charge, but people would probably be willing to believe that corn might produce more, and they're not as prevalent in popular media for people to challenge that notion. The question comes back to one thing - we can design a lot of really crazy ideas into approximate plausibility, but will it serve a purpose? Phones and electronics being charged by maize grain is a good starting point for the whole world, but on its own it's just different for difference's sake. So we have to ask ourselves why would this society charge their phones with maize grains? An obvious reason would be that corn is so prevalent throughout the world that of your phone runs low on battery, it's incredibly straight forward to walk across the road to the corn field, grab a handful of kernels, and dump them into a small device plugged into your phone. But things that influence the way in which one technology is used should, in order to be as believably integrated Into society as possible, should also come up in other ways. Corn husks being used as a common crafting material for instance, a heavily corn based diet, and a society that itself is laid out to compress human housing use of land, and expand the use of land to grow as much corn as possible. No single idea is likely to be too weird to be plausible, but they're also never going to exist in a vacuum. These concepts layer on top of one another like threads in a tapestry. At the end of the day, everything we create works towards creating a larger cohesive world, not just a one off thing.