The simplest way to start creating is to build what you want to see in the world, as soon as you are barely capable of it. If you keep thinking "Erotic modernist haiku pierces my heart, I wish I had more of it to read", this is a clue that you should start writing erotic modernist haiku. If you keep wishing that there existed music that combined bagpipes with throat singing, this is a clue that you should record music with bagpipes and throat singing.
This sounds obvious, but it's easy to underestimate how much passion can get you over the first hump of creative output. Early on in learning how to program, I stayed up all night coding a library* in C. It was the most exciting thing in the world. This was as soon as I learned about hash tables and before I learned about databases, which is a bit like deciding to build a house after learning about doors. Did I create anything close to something humans would use? No. Did I learn a lot about control flow and state management? Yes!
This effect is further compounded because if you're passionate about what you're building, you'll be excited to tell friends about what you're building. Then, they'll be excited for you, fueling you further.
I think "build what you want to see more of in in the world" also applies to creative inspirations. I love Prurient's noise music. I wish there was a lot more like it. The simple solution has been to shamelessly rip him off.
As a cautionary tale, consider: as a child, I wrote 500 pages of chapters and notes for a 12-book fantasy series. It was basically Chrono Trigger but I recall there were dark elves too. Then, at some point, I realized how wooden my dialogue was. I had all these boring scenes to write. I had to admit that one of my characters was a Gary Sue. At the time I didn't want to have trouble writing dialogue, trouble writing scenes, with non-overpowered characters. So I didn't write! This was a huge mistake! I had barely become capable of writing yet I stopped building what I wanted to see in the world.
The consequence of this is that fifteen years later, my dialogue was still wooden. Though I had the patience for writing boring scenes and the knowledge to avoid overpowered characters, I had new fears crop up, like pacing and theme. If I had only kept pushing when I could barely write, and was having fun with it, I could have leveled up in a few of these things while ignoring others.
Luckily, this time I pushed through while barely capable, because I had something I wanted to see in the world: a story about an effective altruist stuck in a time loop. Wooden dialogue or not, I wanted this story to exist, so I made it exist! If I'd been writing for the last fifteen years, I imagine it would be stronger. Nonetheless, by pushing through, I think I've leveled up from 'barely capable' to 'a little capable'.
As soon as you are capable of building, you should start. It doesn't have to be any good. But it should be something you've always wanted to exist. You can come back years later and patch it up. Or, you can simply enjoy the progress you've made, from there to here.
- A genres and authors library, not a functions and structs library.