Well this is going to take a while:

Most of the pve is solo, you solo through the main quests yourselves, though there are dolmens which at low level take a few players and group dungeons there is group dungeons, there 1 group and 1 public dungeon in each zone. The group dungeons means you need to find a 4 player group for, try using the group finding when your a bit higher. The public dungeons are just dungeons but are quite difficult so it's recommended you form a group with people outside or inside the dungeon.

At end game pve there quite a few group pve, veteran dungeons, dragonstar arena, trials (12 man dungeons), craglorn which is a huge pve zone thats designed to be done in a group of 4.

You'll have zones that go up to 40-45 or something they'll you'll go to another zone for 40-50 which i don't want to spoil for you.

When you hit 50 you'll become veteran rank 1, this unlocks the champion system, veteran dungeons etc.. and unlocks quite a few things, you'll then quest through the other factions zones (both of them) until you hit around vet14.

You can play however you like but each class that 3 class tree's and thats the only difference from the other classes, you can use any weapon you like, use any skill from the neurtral skill lines, bow wielding sorc, stave using dragonknight etc...

However until your vet ranks you shouldn't be bothered about picking a final build as you can respec any time keeping your skill levels. Just enjoy the game, research triats and level your crafting. etc...

The 2 answers above give a lot of good info. Just to elaborate on a few points though. Each zone that you progress through offers 3 phased group dungeons (designed for 4-man groups) 1 in your home faction zone the other 2 in the other 2 factions that you can port to, 1 in coldharbour, and 2 in IC if you buy the DLC (total of 18 dungeons). For example the 1st zone group dungeons are Fungal Grotto (EP), Spindleclutch (DC), and Banished Cells (AD). In addition when you hit vr1 you can do the vet dungeons (there are 10) These are group dungeons that continue the storylines in the dungeons. These are all repeatable and scale to the level of your group leader, but all have a minimum lvl corresponding to the level of the zone they are located in. in addition when you hit lvl 45 you can do undaunted pledges, which are daily quests to complete 1 of the group dungeons, and at VR1 you can do vet pledges for the vet dungeons.

Level progression is designed so that levels 1-50 take place in your home faction zones and coldharbour. vr1-5 is silver territories and takes you through the 1st of the other 2 factions zones, vr6-10 takes you through the 2nd of the other factions zones. Which faction you do 1st, depends on which faction you start with. You go counter clockwise around the map. If you start as AD, you do EP for silver, and DC for gold.

However, vet ranks will be disappearing from the game. ZOS is working on making the champion point system a replacement for vet ranks. (CP system was added post-launch) Exactly when and how this transition will happen is unknown, it is still in development. For more info on this check out some of the other posts on the forum (but be forewarned those discussions can be quite acrimonious) or watch some of the ESOLive episodes (ZOS's twitch show) on YouTube.

As far as main cities, every zone has 1 main city with 5-6 guild traders, but all 3 factions have capitols, with 6 traders, they are located in the 2nd zone you progress through. That is where the Undaunted enclave is located (where you pick up the pledges) and see more traffic than most other zones, and have some of the larger trade guilds. The 5th zone in all factions has the vampire and werewolf shrines so they are points of interest that attract players also. However the trade capitol of the game is Rawl'kha in Reapers March (AD 5th zone) it is the most logically laid out of all the cities, with all amenities being easily accessed, and the largest trade guilds have their traders there. It is accessible by DC in silver and EP in gold.

Draxys wrote: »

For the stealth mage thing, you could try a magicka based nightblade. A lot of the NB skills synergize with stealth and have a life-steal theme and that class is kind of the jack of all trades at the moment. By far the most popular class for solo players and pvpers.

I agree with Draxys, for blood mage, stealth mage, stealth archer type builds NB offers more versatility, whether you go stamina or magicka. But there are other skill lines that can be accessed by any class. Vampire or werewolf (can be 1 but not both), 3 guild skill lines (fighters, mages, and undaunted), legerdemain, soul magic, and 2 alliance war skill line all have skills and passives that can be selected.

Gear and gold gain is not very fast in the game. can't think of much more to say about this, other than guild traders are a good way to make gold.

Here is a link to a great site that has a lot of info for any player, I visit it often:

http://elderscrollsonline.wiki.fextralife.com/Elder+Scrolls+Online+Wiki

If you play on PC, here is another great site for addons:

http://www.esoui.com/addons.php

Thank you all so much for taking the time to help me out and explain some things to me! Between you all and an article I found on Tamriel Foundry, I've got a decent grasp of what's up and where to go and what to do and what to expect. So thank you!!

The last questions I have are:

- Can I join both the Fighters Guild and Mage Guild? Or do I have to pick one?
- Is stealth a viable option? Anytime I try to sneak around, due to high population, it ends up being kind of unnecessary because someone manages to swoop in before I do. I think a stealth mage build would be need. I think I will check out the Nightblade instead of Sorcerer.

There are 3 NPC guilds fighters, mages, and undaunted, and you really SHOULD join all 3, they do not count towards your 5 guild limit. Stealth is essential in PvP, it just slows you down in PvE. If you go invisible as a NB mage you do not need to crouch as well, so you will move faster.

Joromarr wrote: »

Can I play through all the zones on one character or do I have to make a character for each faction in order to experience the other 2/3 of the 1-45 zones?

Yes! you can play all the content with one character...
Yes! you should make characters in the other factions!

having a character in each alliance lets you try new fun things, & to get the most fun out of your guilds too!

Joromarr wrote: »

- Are there any "main" cities? From what I've gathered, most zones have 3 towns/cities, but does each pact have a major hub as is typical in other MMOs?

there is one "Main" city on every map, you can find great towns with lots of services, but only that one "Main" has the bank.

& on the PvP map each alliance has two safe zone gate areas, again only one of them has the bank.

Joromarr wrote: »

- I am confused about the classes... all my skills are limited just to three level trees (Daedric, Dark, and Storm I think). So... I dunno. Even some of the reading I've done online leaves me confused about classes and skills in ESO

as you work up any active skill you will get the opportunity to morph it into an improved skill of your choosing.
between class & weapons skill lines you will find a combination that is effective, sustainable, and fun!
& what passives you choose will make a big difference, like medium armor sneaking bonuses.

& my advice is, have those soul gems on you!