To be honest the main storyline quests tend to tell you absolutely everything you need to know about the games mechanics. There might be one or two things it doesn't say straight up but I can't think of them off the top of my head.

Best advice I can tell you is to stick with one job until 50 except for leveling your sub classes to unlock your job. http://ffxiv.consolegameswiki.com/wiki/FF14_Wiki <- This doesn't have a ton of info altogether but it has job and class info.