When meeting someone,I notice whether they approach me with eye contact and an outstretched hand to shake.I always notice their handshake as well. I do not relate well to a first meeting if the person is boisterous or arrogant.I like a calm and cheerful demeanor. Being an ex tradesperson often covered with paint,I am a great believer that 'clothes do NOT maketh the Man (or woman!!!)!!!
The first thing would be their appearance (obviously we haven't spoken yet!) then it would be things like do they look you in the eye when talking...do they listen to you as well as talk about themselves...do they have empathy in general....do you feel 'a connection'...I believe there is a chemistry, even with the same sex...can they laugh at themselves...better stop here!
Do you find this gives you an accurate idea of the person?
I have naturally curly hair which at times has been untamable. I had people tell me they thought I must have been a drug user, because of my hair! A very unfair and inaccurate judgement of me in my opinion.
For males probably hair first, then eyes and how they're dressed (I have a 'thing' for men with a full head of hair!). For women, it's probably what they're wearing and then their hair. Which all sounds rather superficial when you write it down!