Outfits are SO important for senior pictures but the #1 most important thing for a senior session is be YOURSELF! Its fun as new trends can be keep in mind to stay true to yourself! Bring outfits that compliment your style and who you are! My personal favorite outfits are casual graphic tshirts, boyfriend style jeans, barefoot, layers, maxi dresses and flowy skirts! My big no-nos are neon colors, bright whites, tight fitted dresses and shorts, exposed bralettes.
As far as how many outfits I recommend styling AS many outfits that come with your session but bringing 2 back ups! Lots of accessories and shoes!
ps. I am VERY into fashion so if you want my help/opinion I would be more than happy to help you!