1. Lots of makeup - I don't think this neccessarily makes a girls looks easy.
2. Showing lots of skin - possible indication that either you love your body and want to show it off or you are trying to get attention. It could make you look easy as you are giving guys an invitation to objectify you and put their hands on you.
3. Touching guys - this could be seen as being easy as you are being forward and flirting a lot. Guys could take this as a clear green light that you are DTF.
4. Flirting with lots of boys - Again, it could seem like you want attention from guys and they make think you want to have sex.
I saw your outfits. Although they are quite provocative and show lots of skin, I don't think wearing those kind of clothes alone will give you a label of being easy. Your behaviour may add to the assumption that you're easy. However, you must remember that you are wearing these outfits to school and you are young and surrounded by horny teenagers everyday. So in that environment people may in fact mistake you for being easy and wanting attention from guys. You may end up only attracting guys who only want to get laid and who are looking for an easy girl.
I think the outfits are nice as long as you are comfortable in them and aren't wearing them to gain attention then I see no problem.
An easy girl (in my eyes) is someone who makes herself readily available for whoever, no standards, no dignity and no shame. I don't think the way you dress would give off that vibe unless you had an easy girl persona as well.
Everything seems fine, just wear a tank top under the crop top, and under the loose-fitting tank top you linked. Best to keep that stomach covered.
To me, looking easy has to do with both style of dressing and demeanor. When it comes to clothes, some girls wear very tight fitting things that show off every little curve and lump or they wear clothes that barely cover anything, like crop tops without anything under them or short shorts that stop right under the butt cheeks. And some girls give off an "easy" vibe.