How to level up?

[Anova]

Low-level roulette is actually unlocked starting at Lv.17 or so (assumes you can run Sastasha, Tamtara, and Copperbell).

At Lv.10, you should be able to do guildhests. Those will net you the largest chunk of xp solo, as they will award you with the first completion xp bonus for each class you clear them with. The Guildhest roulette bonus xp will also help on a daily basis

Barring that, completing the quest, Rising to the Challenge, will unlock the challenge log and help augment your xp gain on a weekly basis.

Your Lv.10-19 hunting log should help you reach Lv.13 or 14, although you may have trouble killing all the monsters. The guildhests should help with at least 1 level as well. Consider running some FATEs in Western La Noscea if you fall short.

Each starting town has 2 unique quest lines (approx. 10-12 quests) only available to players who started in those towns. Since you started in Limsa Lominsa, you do not have access to their stories. It's sad to say, but you cannot depend on quest xp when leveling alt classes. Instead, you gain a 50% xp bonus on FATE xp and killing enemies for your alts. For that reason, the hunting logs, FATEs, and roulettes are your best bet for leveling alts.