Well, I first started back in 1.0, plus with ARR I started way back in the Alpha test, but for the purposes of this thread, my true starting point in ARR was Phase 4 of the Beta test, which, due being in the Alpha and Beta from the beginning of Phase 1, I at least knew the basics of what to do and where to go at the start, so as soon as I arrived in Gridania's main gate, I immediately switched my class to GLA and upgraded my gear to something better than the starting armour (as I had my 1.0 character transferred into ARR and thus I started with all my 1.0 levels, exp and gear). Then changed some settings in Config such as camera type, controls and setting up the GUI to something I like.

Then immediately unlocked several achievements (quest related ones) which retroactively carried across from 1.0.