Hello mate.
Nice to see some new people joining EQ that actually care about playing right. Etti quite in-game is mostly simple, just respect the players and they'll respect you. However, I wouldn't recommend the use of "/shout"... it tends to get people angry (unless calling for trains). If at all possible when you over pull, either die and get a rez (resurrection, line of cleric spells), or get to a zoneline that is not heavily populated. People usually don't like extremely crude humor in the general chat, but the occasional reference doesn't hurt.
Role-playing isn't really enforced by most guilds or groups of players. In fact, it is rare that you will find a true role-player out there anymore.
Guess I'll try this:
Bard-At low end it is a mediocre warrior until about 27-30, where you can charm/swarm kite. From then until 61 you will be a decent puller, can slow (a little bit), and can do most things a group needs (mana song is amazing). At 61 you get (after 6 aa's) fade, which will TREMENDOUSLY help your pulling ability. You will be top notch in raids for pulling. Most songs (with the exception of the targeted area effect direct damages) cost 0 mana, but fade costs 900. Bards can pick locks (though less efficient than rogues). They can also track, forage, sneak and hide (less efficient than druids/rangers, or rogues, respectively).
Druid-Excellent soloer, can group, as well. All around, a good class to start with. Can heal some high-endish zones such as RSS or MPG, depending on gear. They can port themselves and others to places around Norrath with their spells.
Beastlord - While many may argue that high end raid geared beasts are great damage dealers stand-alone, for the most part, these are knock offs of shamen (get a nice slow at 69). They are mostly dependent on their pets for DPS, but the pet is rather nice. They get pet damage procs, and pet haste, etc. A rather fun class.
Berserker - Rather gear dependant, has a hard time soloing, but in a group enviroment, the DPS is nearly unmatched. With a good weapon and some practice in timing, you can destroy mobs.
Cleric - One of the most sought-out classes out there, the best healer. Gets spells such as Temperance, Virtue, and Tenacity (45, 62, and 71, respectively). A rather easy class to play in the beginning, but it can be hard timing heals later on. Almost always has a group, easy to get in a guild.
Enchanter - Crowd control. With the addition of out of combat regen, the enchanter has lost some purpose. (C3 almost no longer needed). However, they have the best haste in the game and are the most efficient crowd control besides a good puller. Rather hard to solo, unless you know what you are doing.
Magician - A wanna-be wizard with an amazing pet. They have pretty decent nukes, but their pet is what makes them shine. They get high damage, low duration damage shields throughout the levels. They have four pet types: Water, Fire, Earth, and Air. (Flashback to Captain Planet) Very good in groups or solo. They can malo, which reduces an enemy's resists.
Monk - A damage dealer, mostly. Can pull very efficiently, and have a feign death ability (similar to fade, but does not make them invisible*). Can solo fairly efficiently with potions, but are best in group situations.
Necromancer - A loaner, mostly. Can solo VERY efficiently, but still can do a group a lot of good. Has a good pet throughout its levels, most are warriors, but some pets are monks or rogues. (Rogue pets have the ability to backstab when behind an enemy, doing extra damage)
Paladin - A mix between a cleric and a warrior. Well equipped, a paladin might very well be the most dangerous force out there. I've heard of them soloing rather difficult monsters with little difficulty. Pretty good soloers. If you can find a steady stream of undead mobs, you are home free. Have a Lay of Hands ability that heals your target for a rather large amount of HP. Get rather nice heals, and at higher levels, group heals.
Ranger - The best bow class. A ranger on raids usually uses his bow instead of his weapons, and does a rather amazing amount of damage. They are similar to druids. They solo very well bow-kiting, and get damage shields and other druid abilities. They are good at foraging and tracking.
Rogue - Perhaps the best dps, argueably. They use 1hand piercing in the primary slot, but anything (1h slashing, 1h blunt, 1h piercing) in secondary. They are the best at sneaking and hiding, and picking locks. They also can pick pockets, although through the years it has become inefficient.
Shadowknight - A hybrid between necromancers and warriors. They have lifetap, snare, and other necromancer abilities. They are not as good damage-wise as a necromancer, and not as good at taking damage as warriors, but they find a happy medium. Usually not guild main tanks, but can tank high end content if they are geared well enough.
Shaman - The shaman is a well-rounded class. They receive damage over time spells that do a fairly large amount of damage, while they get buffs that can boost a group's killing power. They also get health over time spells, such as Torpor, or later ones that do not slow the target's run speed, such as Quiescence. They are perhaps most famous for their slow, which starting at 51 is 50%, and at 60 it is 75%. They can malo, reducing an enemy's resist, and have a decent pet.
Warrior - Warriors are just like you said, meat shields. They take damage better than anyone else, hold the aggression of the monster on them, and get AA's that excell their ability to take damage (tank).
Wizard - Wizards are up there with rogues and berserkers in the dps range, and can deal some SERIOUS damage in short amounts of time. They use direct damage spells (nukes) mostly, but can snare. They can port people or themselves to many different locations.
*Fade = A bard AA that allows the bard to "feign death" in a way. It takes them off the aggression list of the monsters and turns him invisible. If the monster is too close and sees invisible, it will still attack.
Feign death = A monk ability that is received at level 17. The monk drops to the ground and if successful (if not, you will receive a "Yourname has fallen to the ground. message) will cause any monsters that were after you to forget about you.
As far as abbreviations:
BRD = Bard
DRU = Druid
BST = Beastlord
BER/zerker = Berserker
CLR = Cleric
ENC/Chanter = Enchanter
MAG/Mage = Magician
MNK/Monkie = Monk
NEC/Necro = Necromancer
PAL/Pally = Paladin
RNG = Ranger
ROG = Rogue
SHD/SK = Shadowknight
SHM/Shammy = Shaman
WAR = Warrior
WIZ/Wizzie = Wizard
Lol = Laugh out loud
Lmao = Laughing my (backside) off
wtf = what the [Censored]
rofl = rolling on the floor laughing
mob = monster, "mobile unit"
npc = non-playable character
toon/pc/char = playable character
GL = Guild lobby (where you summon corpse with a "rez stone")
GH = Guild hall
PoK = Plane of Knowledge
PoT = Plane of Tranquility
PoSky = Plane of Sky
PoF = Plane of Fear/Fire
PoW = Plane of Water
PoN = Plane of Nightmare
PoP = Planes of Power expansion
PoJ = Plane of Justice
PoI = Plane of Innovation
LoY = Legacy of Ykesha expansion
GoD = Gates of Discord expansion
OoW = Omens of War expansion
DoN = Dragons of Norrath expansion
TSS = The Serpent's Spine expantion
CR = Crescent Reach
TBS = The Buried Sea expansion
RoK (Retired abbrev.) = Ruins of Kunark expansion
SoV (Retired abbrev.) = Scars of Velious expansion
SoL = Shadows of Luclin expansion
CC = Crystal Caverns/Corathus Creep
LDoN = Lost Dungeons of Norrath expansion
DS = Damage Shield
DPS = Damage per second
baz = bazaar
NL = Netherbian Lair
DSP = Dawnshroud Peaks
GE = Greig's End
ME = Maiden's Eye
port = druid port spell
ding = level-up announcement
idk = I don't know
idc = I don't care
(The above 2 not used often)
atm = at the moment
omw = on my way
lfg = looking for group
omg = oh my god
ISTFWTG = I'm so tired from writing this guide.
I hope it helped some
Please note that this is just a brief overview, I appologize for any major missing information I may have forgotten.