
I'd personally recommend watching Brandon Sanderson's lecture on world building. He does a good job of easily breaking down ways to make a world feel... well, like an actual world. This lecture is just one part of an entire series meant for writing fiction (he also has stuff on creating magic systems and etc), but the information could easily also apply to other mediums.
[youtube]v98Zy_hP5TI[/youtube]
[youtube]v98Zy_hP5TI[/youtube]