If you plan on levelling up multiple jobs, leave the quests in the cities other than your starter cities alone (Other than storyline of course). It'll make your first class a little harder, but ease up on the second classes.

Keep up on your hunting log, it's easy exp and doesn't take long to do it. To kill two birds with one stone, many are quest mobs too. If they kept it in, also, some were dungeon mobs, so it was best to have it done when you were running through

Aetherial gear (Pink) from dunegons actually has randomised bonus stats on it. Even if it's the same item as you have, check to see if it's an upgrade to what you have, if it's not, consider passing on it so someone else can grab it.

Alt + R is how you reply to tells, and if you want to repeat something you've recently said (Or if you messed up your chat channel), press up when you've clicked inside the chat box, it'll have the most recent thing you've said so you don't have to type it out again.

From what I've seen, they haven't nerfed FATE exp (Rather, they've boosted it with the 50% exp bonus for secondary classes) so if you see a FATE, go try and do it! It's a lot of EXP for very little work, and in some cases, can be faster than dungeon EXP.

Leves, IMO, are best used for gathering and crafting classes over battle classes. They don't get the bonus exp that battle classes do, so leves are a very good supplemental to just grinding recipes/farming. Also, if you turn in a HQ item to a crafting leve, you get a 300% bonus!

Even though you can buy dyes at level 1, you can't dye your equipment until you complete a Lvl 15 quest over in Vesper Bay (Near Horizon in Western Thanalan). There's a dye seller in every one of the big cities with a lot of choice once you can dye.

Don't be afraid to ask for help! For every jerk out there, there'll be more wanting to help you out there.