Girls can sometimes be unsure of whether a guy is flirting or just being friendly. This Take is intended to provide a few pointers to the girls who sometimes find themselves puzzling over a guy's intent. The focus will be on interactions in real life, not online, since you can pretty much assume that any guy who slides into your DMs is flirting (or much worse!), especially if he messages with you frequently.
1. That a guy approaches you in the first place generally means he is flirting
There are some guys who will talk to everyone, but if he has gone to the trouble of approaching you and starting a conversation, you should assume right off the bat that he is flirting with you rather than wanting to discuss cloud formations.
2. He stared at you prior to approaching
This is a telltale sign. He noticed you and felt attraction. He probably approaches right after staring, but in some settings, e.g., at school or work, in a few cases it could have been weeks or even months ago that he (first) stared and now he is ready to flirt. If it were just a matter of being friendly, there would be no delays and no staring.
3. He smiles really wide and looks directly at your eyes
Just being friendly might mean there is a smile as well, but you'll see a broad one that shows his pearly whites (if he's got them). He's attracted to you, is excited to talk to you, and wants to show you he is friendly, also to put you at ease as well as to make his interest clear. Looking at your eyes in conjunction with a broad smile helps build a connection.
4. He displays some nervousness in body language and facial expression
See also #3. This won't be present all the time, since lots of guys can flirt without displaying any outward nervousness, but if you can detect it, it's a telltale indication that he is flirting since just being friendly is unlikely to make him nervous to that extent or even noticeably nervous.
5. He stands close to you and touches you
Mind you, this doesn't mean that he totally invades your personal space, but he'll be closer than if he is just being friendly. Before the me too movement, he'd have been more likely to touch your hand, arm or, rarely, even your shoulder, but this may still occur in some cases.
6. He finds something in common with you
This may stem from him noticing something about you, knowing something about you (school, neighborhood, or business environment), or it may come out as the conversation progresses. An example of this approaching the girl walking her dogs when he has some or likes to pet them and talking about them as an icebreaker.
7. He teases you and perhaps uses self-deprecating humor
This has several purposes. It's to get you to relax, feel comfortable with him and show he's a fun guy. It also provides a great opportunity for feedback, i.e., how you react. This can also be used to push boundaries to see how far he can go with you in terms of conversation.
8. He tries to impress you and he compliments you
This is also telltale, as there is no need to do it if he is just being friendly. The compliments are way to tell you what he likes about you and that he's interested. He'll also laugh at your jokes and like everything you say.
9. The longer the convo goes, the more obvious it is that it's flirting
There is no need to take a lot of your time if he is just being friendly. I met the woman I married on a transatlantic flight, which was great since I had nine hours to talk to her. Despite that, she still thought I was just being friendly. Flirting can be done in a couple of minutes, but, the more time he has to make an impression, the better.
10. He suggests getting something to eat or drink
It means he finds you interesting and wants to extend his time with you to make even more of an impression and just enjoy your company some more. This means now, not just a vague mention of some time in the future. It shows he is really into you and wants to extend his time with you.
It's important to remember that in most cases, the feedback you give him in terms of body language (especially smiling and looking into his eyes) will guide how he proceeds. If the feedback is positive, he'll be buoyed to do more, if your body language says you're bored, he may try a new approach or just find a way to bow out.