I usually take the lazy approaches.
Maps: Google EarthPros: Fully interactive, can readily designate precise locations, zoom function, street-view, can link to websites of local businesses and buildings to figure out what that place is about well enough to reasonably contact the owners and get permission.
Cons: Bandwidth-hog, it's google, only does RL locations, can get lost (yes, on a map, using a map), and some people don't like the idea of you playing 'pretend' using their property as a basis for anything.
(
upside is, at least you aren't LARPing on their property)
Existing images:Pros: readily available, minimal art skill required, time-saver for common objects in need of extreme detail
-May also work for strict fandoms
Con: Can spend a lot of time cruising for the "perfect" image, generally not interactive.
-When working with strict fandoms,
this may happen.
Composite of existing images:Pros: allows players to use readily available images to mix and match the appearance of things using that thing called imagination, allows for customization.
Con: Time spent looking (although not as bad) and requires imagination, not interactive.
User Modified/annotated images: Includes template-drawings/images.
Pros: allows you to have fun with google-maps and make your own maps with minimal effort
Cons: Not very interactive (interactive being, to tell the editor to re-mod and clarify a subject, which is time-consuming)
Freehand drawings:Pro: You get it exactly how you want it, only have yourself to blame if it isn't right.
Con:
HUGE learning curve.