Final Fantasy XI is based on a job and a subjob ffxi gil system. The starting jobs include warrior, monk, thief, white mage, black mage, and red mage. These jobs are essentially broken into two groups, front line and back line jobs. Warrior, monk and thief are front line jobs and white mage, black mage, and red mage are back line jobs. Here are some key job differences to help you decide what job you want to start with:

Warrior - Warriors in FFXI are your basic damage dealers (DD). If something needs bashed, they bash it! They excel at most weapons in the game, one drawback to this is that they may need to keep many different weapons skilled up simultaneously. They can also serve as a tank job in earlier levels.

Monk - Monks are also excellent DD. If there's something to smash, they smash it! Unlike ffxi gil warriors, monks specialize in one type of combat which is hand-to-hand. They specialize in undead, against which their damage is truly staggering, but they are excellent DD for any mob.

No matter how great your game skills are you will need the Gils to get your equipments, armors, weapons and other items. Early in the game, having the gears will help you advance to higher levels at a faster pace than others can. Here are some good tips to start your career in Final Fantasy XI.
Warp Quest
First and formost, Warp Quest can get you about 10k gil within an hour. It is important for you to start with 1k to purchase a slime oil. After you've purchased the slime oil, bring ffxi gil to an NPC named "Unlucky Rat" in the Metal district of Bastok in exchange for a warp scroll. The scroll sells for about a good 7-10K. Seems easy? Well slight problem with this method is that you will need to have enough fame built up before the NPC will take your slime oil. You will be required to run around town doing low level missions to get your fame up. This is where it gets a little time consuming but 10k gil an hour for a lowbie is really good. You can also redo this quest by creating a mule account and transferring 1k gil to that character.