Most Helpful Girl
i know this might not be what you want to hear, but every guy is different, therefore its hard to make generalisations about what style guys like a girl to have. When you're shopping for clothes, don't think about whether a guy would think of you in the clothes, think about how they might make YOU feel. If you feel comfortable and confident in what you're wearing and if you think you look good then it'll show I promise :)
You said that you usually wear things like skinny jeans and graphic shirts and that's absolutely fine if that's what you like! but ocassionally mixing things up with what you wear, and wearing something a little different from your usual style can feel great! experiment with different styles and you might find a new one that you love! maybe start small by wearing a bit of a girlier shirt, or get a plain fitted one and use some feminine accessories.
Moving onto makeup, I know for a fact that makeup makes me feel much more confident, even when its just a little bit. Maybe wear a pink lip gloss and balm if you don't to add a little healthy looking colour to your lips. and one product that I rarely go without is mascara, it literally takes me 10 seconds in the morning and it does wonders to just brighten your eyes and frame those pretty peepers :)
I know this sounds so corny but I am positive that you are beautiful!
hehe sorry about the essay but I went through a similar thing and its just a part of growing up!
comment if you have any questions :)