Most Helpful Guy
Okay, blushing is nice and cute but it also states that you are not confidence. And I am not saying that is a bad thing I am just stating it so you understand how a guy is interpreting it. My suggestion to you is to smile (really smirk) and nod back to him acknowledging that you noticed him looking at you and appreciate the compliment. Because it really is a compliment right, he is staring because he finds you attractive. It doesn't mean anything has to develop from it and technically you don't have to talk to him. He is just saying you are attractive. Now by you nodding back you are putting him on the spot and he has to make a decision. Do he approach you or not. Must guys will not approach because they are afraid to make that move. Many will not approach because that is all there is to it meaning they just find you attractive and don't want anything else.
Flirting is awesome...I love flirting but it gets me into trouble because it always leads down a road I don't always want to go. So understand just because you flirt back does not mean you obligate yourself to anything. Just when they approach if you want to talk to them talk, if not then let them know that you are not really looking for anything serious and appreciate the compliment and go on about your business.
Hope that helps
Old School D