Undecided Question

Make up/general beauty driving me crazy, help?

Hello, so i recently started hanging out with girls who are all stunningly beautiful but have major beauty routines. Having been a tomboy most of my life im a little confused about all of this stuff, i stol a copy of my friends cosmo hair & beauty edition & i love it but… There are so many different things in it so now im really confused. So i'll give u a run down of my skin type & u can let me know what u think.

I have olive skin that is pretty normal apart from some trouble with blackheads the occasional pimple & i get quite dry on the sides of my nose thats really it.
so pretty much my question is what sould every "average girl" have in her make up/beauty case?
I have the basics like foundation, eye liner, mascara, a lil eye shadow but is all of this primer different under eye concealer & contouring necessary.

Thanks :-)