
I don't know about leveling second jobs past 50 (I haven't even gotten my first job past 53 yet...), but for leveling to 50, I do something like this:
1-10: Hunt log and class quests
11-15: More hunt log, a few FATEs. Guildheists for the first time when I unlock them (plus the daily guildheist roulette).
Once I get there, I'll queue for each dungeon in turn once I reach the level. With the chain XP bonus, this will get you a level. Then I'll do the daily dungeon roulette. That's another level. FATEs and more hunt log can easily take me through the 3rd level... then I get to another dungeon's level! Rinse, repeat.
1-10: Hunt log and class quests
11-15: More hunt log, a few FATEs. Guildheists for the first time when I unlock them (plus the daily guildheist roulette).
Once I get there, I'll queue for each dungeon in turn once I reach the level. With the chain XP bonus, this will get you a level. Then I'll do the daily dungeon roulette. That's another level. FATEs and more hunt log can easily take me through the 3rd level... then I get to another dungeon's level! Rinse, repeat.
Characters:Â Ojene Suinuet, Jophoix Suinuet