Thousands of single men have been surveyed, are these are some of the more common responses they gave to tell the difference. Be aware-some of these signals can be subtle, so watch closely.
1. The Smile. Everyone has a different smile. Some people smile with their mouth closed and some smile with their teeth. (And some guys are just plain shy!) However, if you notice him smiling at you with a gleam in his eyes, there’s a really large chance he is interested in you.
2. He Gives You Special Treatment. When he talks to you, he leans forward and gives you his undivided attention. Even if other friends he may know approach him, he may exchange pleasantries, but that encounter is fairly brief, then it all comes back to you.
3. He actually remembers what you said. And in many cases he will come back to something you said 10 minutes ago, recalling your words with impressive accuracy. That's a strong sign he is very engaged in what you have to say...and you in general.
4. Watch how he reacts to other women in a social setting. The key thing to note here though is some guys are just naturally flirty and charming around women. If he treats you the same way, he probably isn’t flirting. HOWEVER, if other women friends approach and he "dismisses" them fairly quickly-even if they seem to want to stay longer to talk - that's a STRONG signal.
Now a quick movie reference....
6. He's Doing That "Leaning" Thing. Remember that line in "While You Were Sleeping?" There's a lot of truth there. If you notice him lean in and turn his shoulder to you while you are speaking to him, he is subconsciously focusing on you (and probably flirting)!
7. He Asks You If You’re Single (Or Hints At It). If a guy ever expresses interest in whether or not you are single, he's usually curious for a reason.
8. He gently teases you. Particularly in the younger male ages, they're trying to get you to smile and/or laugh at their gentle observation. Many of these moments reveal he's noticing you more than just the average gal.
9. He passes THIS eye contact test. Try this: Look over his face for around 3 to 4 seconds (don’t make it awkward and hold it too long!) and then look away. After a second, look back at him – if he holds eye contact with you he’s definitely interested. ALSO, he glances towards your mouth he’s REALLY interested.
10. He's a little nervous (and perhaps a little clumsy). Generally guys aren’t nervous around women they aren’t interested in (most of the time), so if he’s nervous around you, that’s a good thing. It means he’s probably worried about making a good impression on you to get you attracted to him as well. (I ran into walls and tripped over things when I was around my would-be wife!)
11. He's blushing. Some guys are just plain shy! If you notice that a shy man is blushing around you, it’s one of the most apparent signs he is trying to flirt with you. Any guy can blush when flirting though, so this does not just apply to shy guys.