Face, regardless of gender. Tells me of their current mood, and whether they look like annoying persons or not. The latter is surprisingly accurate. If it's a male with a neanderthal-esque face, approach with caution. There's no way to tell for sure until you've spoken to them, of course.

Also, shortly after face, i check their attire. If they're dressed in a "gangsta" manner, my initial impression is lowered A LOT. So far, only one "gangsta" person has managed to surpass my expectations and befriend me. For the most part, being "gangsta" involves being a dick to outsiders, apparently.

I look at there chest if walking by...

And there ass if there in front,

maybe there legs

and i look at there face if im talking to them, (maybe look down at my shoes, just look have a quick look at there chest )

^^^^^thats for a girl

Generally I take in the kind of person they are by their clothes, build or basically anything they have control over as this is the best judge of character without engaging with them directly.

In women the first thing I tend to notice is the eyes, nothing works better on me than nice eyes. Don't get me wrong I'll take a look at what she has got on show but I won't stand and dribble over her.

Hmm... good question. I usually look at people's faces first, women or men. Preferably the eyes - I like looking people eye to eye when talking to them.
As far as taking a peek at the merchandise, everyone does.

I look at the eyes first, then the hair and if it's a girl I just look at her chest by looking some where down.
If it's a man then I usually look at his nose for some reason.

fristly the face in a girl
but if i watch his boobs(if its big)
i cant watch his eyes .
but full body

i usually look @ the persons eyes first. or the shoes xDDD

eyes if its a girl hair if its a guy

Boy: Face
Girl: B Face xDDDDDDDD

Face if it is a girl, eye if it is a boy.