Worldbuilding Wednesday: Resources/Methods

Something I would love to pick people's brains about is the use of existing resources for wordbuilding or, conversely, the decision to ignore existing resources and make your own, especially when it comes to alien cultures. For a lot of the playable species in SWTOR, finding information on Wookipedia or other such resources can be kind of a grab-bag--"official" information on a species or culture might be sparse, or there might be a bunch of it but it's full of contradictions and retcons, or maybe you just plain don't like it. On the other hand, rejecting existing information and making up your own headcanon for alien cultures gives you a lot of freedom, but can be an intimidating and uncertain process (at least, it can if you're me). So what do you do?

In theory, I like a sort of middle-ground approach: see what existing information is out there, use it if I can, make up something of my own if I have to. But--perhaps I'm still fairly new to worldbuilding in the SWTOR universe--I find that in practice I'm really insecure about striking out on my own and prefer to fall back on either what I can find on Wookiepedia, or worldbuilding and roleplaying resources that have been created by other players.

So, questions I'm throwing out for anyone who wants to answer them: what's your approach? Are there other resources besides Wookiepedia you like to use when looking for existing information? Are there any player-created resources you're particularly fond of? If you prefer coming up with your own headcanon to using existing information, how do you tend to go about it? Basically, worldbuilding: HOW?