I guess I will answer using my own perspective and what I would do.
When I'm attracted to someone, I listen to every word the guy is saying. I'll be attentive, make eye contact, and when appropriate, respond back and just let them know I'm interested in what they are saying. There is always the cocked head, that shows all of that.
When I walk with someone that I'm interested in, I'll keep my hand (on whichever side he's on) free and dangling. Sort of a sign to hold my hand. I don't cross my arms (unless I'm shivering to death) when I'm with someone I like. I only do that when I'm with someone I'm not interested in, which is a sign that I'm closing myself off to them.
Before separating, when I give them a hug, I try to say something nice to them in their ear during the hug. Could be a quick "I had fun" "Thank you for coffee" etc. etc. And pull away, give him a smile and walk away.
Semper Fidelis.
I believe in love, I believe in faith, I believe and hold on to hope.
I believe that falling in love can happen over time, or even at first sight.