Below are some helpful links that will help you with the game. There are several sites out there, so feel free to post your favorite if it's not already listed.

This site gives you great information on quests (with requirements, etc), items and most everything in-game:
http://ffxiv.gamerescape.com/

Also gives information for quests, but I prefer this for a quick reference on the classes, spells/abilities, hunt log, etc:
http://ffxiv.consolegameswiki.com/wiki/FF14_Wiki

Interested in changing your chocobo's color but confused as all hell as to how to get that done? This site is by far, in my opinion, the most simple way of explaining what materials you need. You can select what your bird's color currently is, what color you want it to be and it'll tell ya what you need:
http://ffxivchocobo.com/

There are of course the basics, such as YouTube and Reddit. And, obviously, the internet is full of other sites.

…and lets not forget the all important:
http://www.ffxivguild.com/
Great site for help with leveling things.

This was given to me by Tier (aka Twilekku). Helps you determine which line to choose in the daily Cactpot located in The Golden Saucer.
http://super-aardvark.github.io/yuryu/