As far as world-building is concerned, something I'm doing with my current story is making "fun facts" and putting them at the beginning of each post (this world's cultures, rumors, sayings, holidays, scientific discoveries, history, etc.). Most of them are nothing more than more immersion for the reader's benefit, but occasionally, something WILL BE plot important later on. I think it's a creative way to foreshadow future events without being overly blatant about it in the story proper (HEY GUYS!!! THIS WILL BE IMPORTANT LATER SO YOU BETTER REMEMBER IT NOW!!!).