Tips for first-time iPhone user!

So this week I'll purchase a 16 Gb, space gray, iPhone 5S. I was between this phone and a Nexus 5, but getting one here in Peru is practically impossible, so I settled in the iPhone. This will be my first actual smartphone experience, as my past phones were a cheap old Nokia and a 2012 Blackberry Curve.

I already have in mind a set of basic apps (Facebook, Evernote, Spotify, WhatsApp, Google Maps, etc.) to download, but I will appreciate any kind of apps and accessories recommendation and suggestions or tips for embracing this experience adequately.

BTW I am in 15 years old and in my first year in high school. Now you have my life context