Like what Lexi said, paitence is key. If you get impatient and accumulate denials and HPs just because you weren't able to wait, it's just going to hurt you for the next 2 years.
Your best bet right now is to keep applying for Amex cards, since they backdate, and it's a SP if denied. You basically got nothing to lose and everything to gain.
For now, you're doing really well for the stage you are at. Just let your accounts age.
a bit irrelevant:
I assume you're still in school since your student loan is defered till 2017. Instead of worrying about what cards to get, focus on your studies!
GPA is (almost) everything. Get a high GPA, land a good job with a high income (which translate to high buying power and greater ability to repay debt), and getting most of the cards out there and high CLs will be a piece of cake.
JPMorgan Palladium (100k), AmEx Platinum (NPSL), AmEx SPG (46k), AmEx BCP (42k), Chase Sapphire Preferred (47k), Citi Prestige (31k), Citi Thank You Preferred (27k), Citi Executive AAdvantage (25k), JPMorgan Ritz-Carlton (21k), Merrill+ (15k), US Bank Cash+ (22.5k), Wells Fargo (12k), Bloomingdale’s (12.4k), Chase Freedom (5k), Discover IT (5k).