I google just about everything. Sometimes it takes me longer to google something than it does to write the danged post. And of course you wind up with way more information than you needed. Like, you start looking for one specific type of, I don't know, spicy pepper, and you wind up with a bunch of recipes, a list of the spiciest peppers, and whether or not you can grow them where the rp is happening, but also in your own climate zone. Because hey, why not?
I've used name generators, looked up popular names in specific years, regional or language appropriate names. Researched historical dates and events, traditional foods, sea creatures, land creatures, rock formations, the birds and the bees(yes the saying, I wanted to know where it came from, whether or not that was relevant to the post I was writing at the time I can't remember), region specific dialects and idioms, book releases, architects, dinosaurs, prehistoric beasties that aren't dinosaurs, thesaurus is a necessity because sometimes I want that word, y'know, the one that starts with a p? Looked up forts, national parks, maps, old calendar systems, alcoholic beverages, heraldry, dream significance, flower meanings, tarot cards, archery, anatomy, illnesses, mental troubles, historical diseases, historical reactions to health problems, old cures, mythology, children's rhymes, swears, ASL, swears in ASL(and other languages), dictionaries are useful.... Sometimes I'll look up punctuation, too. Also, fandomsmust be researched sometimes if my character knows more than me. Damn characters that know more than their creators, am I right?
Googling is fun. Wikipedia is pretty awesome, and a time sink. Terrible, horrible time sink.