[MinaciousGrace]

Originally Posted by Litodude

these are the questions you ask yourself, in order:

"who is the jungler?"
"what are the gank paths?"
"ok, i will ward those paths."

"who is mid lane?"
"does it look like our mid lane is winning?"
"I don't think so, better ward where s/he might go."

"does top have tp?"
"did top rotate mid to contest dragon?"
"better ward somewhere near dragon but i should be careful."

once you're out of laning phase:

"where do we want to fight?"
"what objectives do we want to contest?"
"i better ward around those areas."

"are we winning?"
"i should probably ward deeper into their jungle."

"are we losing?"
"i should probably ward closer to our jungle, carefully."

if it's, "i don't really know what i'm doing, i'm just rotating to a lane to farm"
"I should probably put a ward down where i THINK they might come from. i also shouldn't over extend if i have no escape or if my flash is down."

this is a pretty comprehensive general list