implication - what it means about things that have happened before or will happen
motivation - why are things happening
a tell - a static descriptive element to make a character "stick" in the mind. A good thing for generic toughs or goons to make them less generic and east to identify to pcs
a look - a dynamic descriptive element which changes ever time a character is seen. could be clothes, could be hair color. Have fun with it. makes different encounters with different gmcs ...well different
speech patterns - how a person talks says something about the person. have fun with it.
don't over do it - too much detail bogs down play and distracts a pc from what they are going to do. They are the center of the world even if they aren't the most important thing in it.
what is the location for? The best places are those which seem to have existed before the pcs enter them and will continue to after they have left them.
what is going on at the location? Are the pcs the center of attention or not? What else is going on around them? is there music? is there a tv blaring or a radio softly playing classical music?
what time is it? is it day or night? does it matter?
is weather a factor? weather creates mood so use it.
clues? props? puzzles? Are there objects to found or things to be seen? why will the pc notice these things?
don't over do it - too much detail bogs down play and distracts a pc from what they are going to do. They are the center of the world even if they aren't the most important thing in it. Choose the best detail over too much detail. Be simple but go deep, to paraphrase Constance Hale.
Things to Consider
taste? A odd sense to use but in some situations can be evocative. The taste of wine, a face full of shaving cream, being buried in mud, drowning in a stagnant pond.
smells? The source of an odor is as important as what it smells like. The smell of a chinese restaurant versus a subway station. pleasant or disgusting odors coming from nowhere will certain create a sense of mystery.
textures? How does the old leather case feel? how does the wall feel? the grip of a pistol in your sweaty hand. textures create direct sensations for the pc thru the GM.
spatial relations? what is close to a pc, what is far away? People? Objects? Odors?Also consider a location as a three dimensional place with an up and a down as well as foreground and background.
sounds? Is it a bass tone or a treble tone? where is it coming from? does it sound mechanical or natural? is it rhythmic? is it melodic or atonal? what does it remind a pc of? what does it remind you of? why are the last two different? ....that is if they are.....
line of sight? what can be easily seen and what cannot be in relation to where a pc is located?
is it important? it should be.
visability? this is as much about internal limits to sight as it is to external. is bright or dark?
how is a place lit? is it foggy or misty or is it clear. is the moon out? is the sun? is the viewer tired? drunk? blindfolded? do they wear glasses? what does what a pc see remind them of?(see sounds above.)
surfaces? are they on the grass or they on tiles or on broken cobblestones?
This was put together quickly and roughly. It may not be the prettiest thing and could have been more detailed. These are valid gripes but that goes against my intent. This was created for my own use as a quick overview to have on hand for quick consultation while running a game. I hope someone will find this useful. - Greyshirt