It works both ways. She's doing it to try to draw you into her, so you're chasing her. If you start to seem to lose a bit of interest, she'll likely try to get you interested again which means that she is chasing you to an extent.
If it is constantly happening to you, you need to look at yourself to find out why. To avoid being friend-zoned you need to have intent. The girl needs to know that you know what you want and know how to get it. Nothing too extreme, just something that lets her know that you might be interested without screaming "I THINK ABOUT YOU 24/7 365 DAYS A YEAR! PLEASE MARRY ME!".
See a cute new girl and get chatting? Instead of making small talk about whatever friends talk about all day, let her know that she's cute. Straight-up, nice and confident, eye contact (but not psycho style), smile "You're pretty cute". Don't overdo it by barraging her with complements all the time.
She'll probably say "Thanks" or something and blush. After this just talk about a completely different normal topic, but bust her balls about stuff she says, stuff she does and stuff she wears, but in a jokey way.
Touching is a good 'in' too. Nothing creepy (vital not to come across creepy) but just stuff like touching her upper arm in conversation (if you are standing), high fives (be gentle, she's delicate!), thumb wrestling (and cheating to win! 👍) etc.
If you don't touch in conversation normally, you have to be very subtle with starting to do it and touch EVERYBODY you talk to. Friends, girls you like, etc, because otherwise it's a little weird touching one or two girls out of your entire friendship group! Obviously male friends are easiest as you can pretty much get away with any bro-style stuff.
All of the above is helped greatly if you are confident in yourself. Don't doubt your actions unless you KNOW you're wrong/being creepy and weird.
If other guys start messing you about saying "Ha, you think the new girl's cute, gonna marry her!?" just look them directly in the eye and say and do nothing else. Just stare blankly. Teasing is no fun without a reaction.
Don't let things tool you, because you're a cool guy, right? You do what you want (within reason) and what makes you feel good.
Remember that you have decades to find a girl you love, so chill. Just talk, see where it goes from there and don't keep thinking to yourself "how can I get this girl to like me?". If she's talking to you by choice, she probably likes you at least a teeny bit.
As McLaren said, if you have been friend-zoned and value the relationship, move on. Do the above on the new girl who has caught your eye and avoid being friend-zoned in the first place!
. I'm not saying there's anything wrong with that, but most people think there is...
