Advice for a new player

[Taika]

For low level leveling, I've found quests combined with your class hunting log and FATEs the fastest way. Guildhests are ok too, and completing each once gives you a first timer exp bonus (for each class separately). You can also run Guildhest roulette once a day. From level 16 onwards, remember to run your daily low level roulette every day. Make sure you have unlocked your challenge log for bonus exp.

Also, notice that you should level both your subclasses (Pugilist and Lancer) to higher level than 15 to get all the useful subclass abilities for your main job (Bard). You'll want to level Lancer to at least 34 for Blood for Blood and Pugilist to 42 for Mantra.