So, if you are newcomer to the game, here are some hard won tips and tricks. I really hope my memory as to what level and time things unlock are correct, it's been awhile..
Goal #1 = Unlocking Guildleves
Guildleves are a kind of repeatable quest. They unlock at level 10. Upon unlocking these, They can be used and accumulate at the rate of 4 every 12 (I think) rl hours. THESE WILL ACCUMULATE DURING DOWNTIME, INCLUDING BREAKS IN THE BETA. HAVING THESE STOCKED HIGH WILL BE AMAZING FOR FUTURE PROGRESS.
Goal #2 = Completing Ifrit on my main class. Preferably at level 18 or 19.
This is part of your main quest chain. This unlocks your Grand Company (after several run around cutscene quests), which is different from a Free Company (guild). Grand Companies are kind of like factions in WoW, you join them, and doing fates and various other tasks after you have joined reward you with seals that you can spend on equipment, and more importantly, your chocobo. This means that you can achieve your chocobo this weekend.
I want to get this done by level 18 or 19 so I don't waste any XP fate grinding for seals. Once you hit level 20, you can do the chocobo quest for your first mount.
Rest XP:
It's a bit backward, but you DO NOT GET REST XP IN THE MAIN CITIES. I learned this one the hard way. Rest xp also accumulate during downtime, including gaps in beta, so you can come back with a FULL rest xp bar between the Open Beta and early access.
The Teleport System:
FF14 has three different types of teleport systems. One is "Return" - you bind at any Aetheryte Crystal (big blue glowing gems in certain cities/hubs) and you can click this to effectively "Hearthstone" for free once every 15 minutes.
The second is "Teleport" - using this you can instantly teleport from anywhere in the world to any Aetheryte Crystal you have ever visted. This costs gil to use, and has no cooldown. You can also "Favourite" up to 3 locations to teleport to them at a reduced price.
The third is the teleport system within cities. This is called the Aethernet. Smaller Aetheryte crystals are scattered throughout the city and clicking any of them let you teleport from any Aethernet crystal to another Aethernet crystal. Aethernet exists in the 3 main cities. When you unlock all of the Aethernet locations in a city you gain the ability to teleport out of the cities main exits (into the quest areas) from the Aethernet as well.
Starting City, Starting Races, Jobs and Stats:
Your starting city is determined by your class and class alone.
Gridania: Conjurers, Lancers, Archers
Ul'dah: Thaumaturges, Gladiators, Pugilists
Limsa Lominsa: Marauders, Arcanists (and most likely Musketeers coming next, the 2nd Dex class)
Expect Gridania to be the most crowded as 3 popular classes start there and Beta 3 was Gridania only, so more people are familiar with the area.
Limsa Lominsa will also be crowded as Arcanist is a new class that hasn't been playable yet and people will be trying them out en mass.
There is no difference in stats or anything else by race. Go with your personal preference.
Each level after level 10 (I think) gives you stats. These are seperated by class, so adding stats to one class won't affect the stats of a secondary class. Far as we know, just dump these in your primary stat (VIT for Marauders and Gladiators, DEX for Archers, STR for Pugilists and Lancers, INT for Arcanists and Thaumaturges, MND for Conjurers.
Jobs come at level 30 and cannot be used for this Beta, so don't worry about them.
Fates:
Fates are mini-quests that activate out in the quest areas. No one is quite sure how they activate, it may be tied to people completing quest, or it may be random.
Fates usually have some story basis (Enemies raiding, people trying to steal stuff, swarms of enemies due to environmental conditions, or large boss monsters, etc) Upon entering a fate area, you are prompted to temporarily reduce your level (if you are over the maximum level of the fate) if you want to participate.
Doing fates will grant you Grand Company Seals (used to purchase items in their shop, like the chocobo) as well as hefty chunks of XP and Gil. You can receive up to 3 levels of reward (lets call them bronze, silver, gold) depending on your contribution.
I go out of my way to hit all that I see, they're really money for jam. They show up on the map and minimap with icons and shaded areas showing which area the fate covers.
Speaking of De-levelling, it happens in single player instances (important quests) and regular 4 man instances as well. For these it is automatic if you are overlevelled - it will scale you down to the highest level possible, including skills, and stats on your equipment. Out in the field, for fates, it's optional, but if you choose no, you won't get any fate rewards. This allows you to ride through a fate and not get delevelled if you are not interested in doing it.
I may have made some mistakes here, I'm working off my memory. If anyone else has any questions, post them here and I will do my best to answer them.