Wow I'm a lvl 36 DRG and started playing since PS4 launch. How can you guys level that fast?
Every spare waking hour. Also - levequests, hunting logs, daily roulettes and picking up every side mission I could find. Spend a little money on equipment and grind the exp/gil to use and buy it, nothing fancy just enough so you're ahead of the curve on the mission reward items. Always take the money unless it's something really awesome. Good gear allows you to take on harder enemies and get away with it, making the most of exp boosts. Rest in cities, eat food every half an hour, you'll get plenty for free from the story/side missions. Ahead of time put some gil by for the stuff required for your relic weapon, some are quite expensive but by that point some side quests are throwing 2x2500 at you for fetching a box. When you get access to a chocobo mount and air travel, explore the world - uncovering the map gives more exp scaled by level.
I would have had some level 100+ gear by now if it wasn't for the weekly soldiery cap.
I have a recommendation for people in the GAF FC, you already have General/Battle/Event chat filter settings, on a PS4 press the touchpad to highlight that area of the UI and use L1/R1 to change which tab. What doesn't seem to be documented unless you go fishing however, is that you can add at least one extra filter - so I created one which is a copy of general with Free Company chat turned off (along with a few other bits). Then when I'm in a party I need to pay attention to, I just switch which filter is in use.