You gotta be out there more often to know when a chick feeling you or if she's being nice. Case in point:
I used to go to this Whole Foods near my old job and I noticed there was this chick that would always be looking at me. Everytime I'd come in there she'd be smiling and when ringing me up trying to start up a convo. She was beautiful. She looked EXACTLY like that dark skin chick from Girlfriends:
So anyway I wanted to get her number but I was scared(I was like 18) so I forgot what happened but I think I found her on Myspace. I hit her up and got her number there. Nothing came out of it as I had a girl at the time.
Another time that SAME whole foods had this other haitian chick that'd be checkin me out and blatantly asking me if I needed any help. She'd crack a big smile when she saw me. Same thing, I had a girl. Hell, she was LIVING with my girlfriend at the time

.
Most recently I was in a Trader Joes and this light skin chick was brooming the floor and i pointed her to some spilled pasta near me and then she just looked at me and complimented me on my hair. She was like "I like your braids

" *Has dreads*
Me:
Her:

No I'm just playing I always do that with my sister haha.
Me:

Oh okay *chit chat*
She's telling me my hair looks nice and how long i've had dreads and If I would cut em for a job etc etc. she had dreads too. Nothing happened as i was just there to pick up some stuff but I felt like if she wasn't interested, she wouldn't have went off into a conversation about hair and complimenting me.
If a girl is going out her way to talk to you and help you and she's just talking and talking and not about anything store related, she's probably interested. It's happened so many times to me but I always was doubting it even though other people with me told me "Yo she feelin you."