upon meeting a person for the first time:

1. their eye color

2. what sort of mood they're in (i.e.friendly, upset, hostile, suspcious, 
   carefree, etc)

3. whether or not the expression in their eyes differs from the
   impression they're trying to present

4. are they familiar looking?

5. do they seem to fit in with the surroundings 

on first meeting i tend not to notice specific physical characteristics 
other than eye color, apart from general impressions of size, coloring, 
apparel, etc, unless it is very unusual and stands out.  


upon going to a place for the first time:

1.  am i comfortable here, mentally and physically

2.  is it open or cluttered? (if it's not fairly open, i don't like it)
 
probalby a few other things too.  let me think more aobu it.