As a girl, We flirt by either making jokes, Wearing different clothes (i.e. tighter jeans, heels) or acting like we are too good for anyone. If your friends are doing this then they probably like you. IF you really want to impress a girl, have the guts to ask her out. not only will she be flattered, she will feel like you are a true gentle as well as all the qualities she already likes about you. Goodluck :)
I'm 15, been through just about it all, if you like them, go for it, ask them out, but personally I think writing a note or asking through text is overrated, do it in person, you may be reallly nervous but just build up the courage and go for it, it will help you put in the long run, trust me, my boyfriend asked me out in a text, and I told him I would about it, then when he finally came up to me in person and asked I said yes, Good luck!
Well,Ima girl,so take my answer. Well, what you do is try to get close to them. You know, be good friends with those girls. If you get to know them,be sure that's the one! And just go for it! The worst that can happen,is she says "no." So do it. Nothing to be afraid of. (: Good lUCK.