Rock Paper Scissors Game - Built w/ Tailwind CSS

I seem to be getting the hang of JavaScript, but with more complexity comes more disorganization in the code. I tried to keep it simple by breaking down functions into smaller functions, but then it's easier to insert errors in the code or mistakenly repeat yourself (and then forget to change something...).

So, my question to you - what principals and practices do you use to keep your code neat and organized right from the beginning?

Any other feedback on my project is always appreciated!