OK... Where to start?
Strap in, this is gonna be a lot.
Edit: this was typed on my phone... Please excuse any major typos!
what would a girl talk with other girls about, to what extend would she describe certain events, what would she like about a guy, how would she react and think when her crush talks to her, what would she think if she recieves a compliment, about what would she talk with her parents, how important would outward appearance be, or how important is social status to her.
In order to start answering these questions you need to determine what type of character your MC is.
Is she shy, outgoing, flirtatious, overbearing, easygoing, sarcastic, etc?
We tend to be ruled by our emotions, doubly so in writing, so determining what type of character she is will really help narrow down how she will act. For the above questions, I'm going to use myself as an example.
I actually get along better in social situations with men more so than other woman. Straight women anyways. Woman tend to over analyze the shit out of everything, so we often have to monitor what we say to our girl friends. When describing events, focus less on the what and more on how she felt about it.
Writing how she feels about a guy will be more difficult for me to describe, since I'm SUPER gay... But I can go with generalities. The first and most obvious thing is height difference. Unless your MC likes shorter men or same height men, she will definitely notice his height. We inherently want to be protected and having someone to wrap us up in their arms is a huge draw for many women. She will notice his bodily appearance, is he stocky, muscular, how he fills out his shirt. Eyes and smile. I'm gay, but I'm a sucker for a sexy smile regardless of gender. More so from men with a nice jawline. The timbre of his voice will be something she will listen closely to. How her name sounds when he says it.
If he's talking to her? I'm super sarcastic and slightly flirtatious with everyone, but I get easily flustered by compliments and praise. I tend to ramble and overshare when I'm talking, and often not think fully before I speak, which can very quickly lead to some awkwardness if I say something odd or heavy with accidental entendre. When this happens I try to deflect with humor or something quick-witted, otherwise I'll just blush a lot and just sort of get quiet.
Parents depend entirely on her relationship with them and how her parents view her. Is she a daddy's girl, does she get talk about girly stuff with mom, how much of her personal life is she open with them about?
Outward appearance. Oof. This one is difficult. Context. If I'm just hanging out with friends and not attempting to impress anyone, I don't give two fucks about any of it, even if my crush is involved (jeans/shorts, tank top, sports bra, hoodie) I'm a person, and I don't want to feel pressured to always look and be 110%. But if I'm attempting to impress them, I will start with thing that are still in that realm but draw more attention to what I find attractive about myself. For me, that's my boobs. I have 42 G cups. My ladies are bountiful, and despite the back issues I like how they look on me. 80% of my shirts show a lot of cleavage (it's hard not to unless the shirts are oversized). Your MC will do the same. She will wear things that inherently draw attention towards the part of her she finds attractive.
In social settings, I like to be the center of attention. I'm usually the DM with my group of friends, I usually pick what activity we're going to do or what topic we're talking about. Now, if I don't know the people I'm around or the environment I'm in, I'm the exact opposite. I watch to see how people are, how they respond to one another, what level of quirkiness the group has. Once I'm comfortable I morph back into the social butterfly.
OK. I've written a novel. If there's something I didn't cover or something you want more info about, feel to message me.