New Player - Best Leveling Strategy?

[Asheilin]

If you enjoy tanking, I'd risk doing a tank first with a dps at the side that you enjoy.

New player Important Tips

When you pick a class/job, find out what Cross-Class skills you can have. ex. Archer and Rogue uses Lancer (leveled to 34 for Blood for Blood--this is an important DPS increase skill) and Puglist (15 to unlock Bard and Ninja, can get Mantra at 42 (a good support skill that increases healing on all party members in 20y for duration--its good to have, but alot of bards do seem to skip it.)
Galdiator uses Marauder (26 for Mercy Stroke) and Conjurer (15 to unlock paladin and 34 for Stoneskin)

Tips for a New Tank:
Put a Mark 1 on your bars and use it to help your party know where to focus thier damage. It might not always be listened to, but it does help. I cycle 1 on each target as the last one dies, instead of marking 1-2-3-etc.

Flash after every rotation, minimum, until higher levels (after 40 when you get your Emnity/Argo Up stance for Gladiator/Paladin)
Marauders/Warriors get overpower early, but might still want flash (its a Gladiator Cross-Class skill) to help since overpower spam is resource intensive.

[Bdyer]

I would suggest leveling 1 class to 30 and it's required job subclass to 15. Once you get your job, do a full run of potd and see how you like the class at 60. Repeat the process of you aren't enjoying how it plays at 60.

[Lollie]

Unless you are absolutely loving rogue as opposed to equally enjoyable or less so then others, I would suggest leveling that last of the ones on your list as it offers no cross class abilities to other jobs.