I've been working on building a world for my latest story (one that, hopefully, I will soon shelve in favour of finishing some of my others) and having a bit of trouble focusing my thoughts. I decided to go in search of some help online and found this. It's a list of fantasy worldbuilding questions from Patricia C. Wrede and it includes thought-provoking questions to make you consider every corner of your imaginary world, including physical and historical features; magic and magicians; peoples and customs; social organization; commerce, trade and public life and daily life. You should ABSOLUTELY check it out, whether you write sci-fi, fantasy, speculative fiction, historical fiction or anything that takes place anywhere other than exactly right here, right now.
I've also added a link to the link list, with a helpful name like "Worldbuilding Questions" or something like that.
Happy creating, people.