If you're not familiar with FFXII I'd say to get a black mage and a white mage in your first playthrough, both are awesome jobs.
Time Mage is good if you hate farming consumables and want "easy" access to Ribbons since it's the only job that can cast break (Required for Red Chocobo lv 99 trick, see on Youtube), but mediocre otherwise. Haste and Berserk are always good though and Time Mage is the only job that can use both without items.
Red Mage is surprisingly good, but lack of Curaja hurts it. It also needs a few Espers to get the good spells.
Hunter sucks till you get access to Main Gauge and Ninja Swords, then it becomes a solid attacker or a great tank depending on what you need.
Samurai, Dragoon and Breaker are more or less interchangeable since they focus on heavy physical damage more than else.
Knight and Monk are hybrid DD/healer classes but keep in mind that they require a heavy Esper investiment to be good on the healer side.
Archer is considered to be the worst job since bows are slow and inaccurate and its other specialty, item lores, is not that useful if you have a solid healer.
Machinist is almost a must have in weak mode and it's overall decent in normal plathroughs as well. It does get a few useful spells including Hastega but only late in the game.
Measures are highly situational but guns are good until very late in the game.