Most Helpful Girl
The best way is to really build up over the summer. I spent all year working for money so that I could just go out and do what I wanted over the summer.
Figuring out why you want to do is really hard, so I suggest finding fashion blogger online that basically so what you would like to do (then basically buy the same outfits so you don't have to think about thing yourself). I suggest tumblr, Pinterest, lookbook. nu, or Instagram. Also try finding a blogger who has a similar body type.
Once you did a blogger rely on then or inspiration or staple items they have. Also start with basics. Everyone needs a plain white v-neck, blue jeans that work with every outfit, a go to black jacket, and some other staples that you have to figure out for yourself (or you can message me).
Next figure out what girly means to you. For some it just means dressing well, for others it's a certain style. Search every style and figure out what you definitions is.
Also accessories can take an outfit from a 5 to a 10 really quickly
This is all I can think of right now, so message me with any questions or if you want to me to elaborate message me