Ok, I think I use different cues, that may or may not be universal! I tend to play with my hair which means Hey you're cute, "NOTICE ME" I could use help playing with my hair!!! If you touch my hair...I will definitely notice you! If I laugh a lot, "I like you...keep talking, I'm not hearing what I want quite yet, but I am listening..."
I find that the more I am attracted to someone I will stumble for words and stutter, this does not work very well! So if I am quiet, I really like what you have to say! You have my undivided attention and I don't dare open my mouth cuz gibberish may fall out! But I am smiling! If my cheeks turn red, I am physically attracted! If any of the above lead to my blushing, ask me for my number!