Just a Note, I haven't actually had any hands on experience, this is all theoretical, basic MMO Theory. But hopefully quite useful.

The wonderful thing about zOMG is that your character is completely customizable. Using rings, one can make a "Class" or Build to your liking.

However, one cannot simply walk into Mordor with a bunch of attack rings and expect to last very long.

Creating a balanced and useful character is an art, and it takes time, and lots of experimentation. Let's go over the basics.


Archetypes

Archetypes are a staple in MMOs. While you are free to deviate or modify the archetypes to your liking, it's a good idea to know what they are.

The Tank- The Tank's job is to maintain aggro. Tanks need to be able to keep the mobs focused on them, and they need a way to stay alive. Some Tanks are simply really really tough. Others make it so that the enemies cannot land a hit, and some simply heal themselves faster than the enemies can attack. Offensive power is optional.

The Healer- Exactly what it says on the tin. Healers heal people. A Healer's Ring consists of healing spells, status buffs, and a "Rez" spell for emergencies. Rings from the Medic, Chef, and Cleric(?) sets are excellent for healers.

The Nuker- I put on my robe and wizard hat...
The Nuker's Job is to deal as much damage to as many enemies as possible. "Area of Effect" is their bread and butter. They may also have a few cheap single target attacks. Nukers should stock rings that the enemies in the area are weak against.

The Swordsman- Sword in his hand and a chip on his shoulder. This is a "DPS" (Damage Per Second) Archetype that focuses on Melee. They get up close and personal, dealing (and taking) lots of damage. The Swordsmen doesn't really need to use actual swords, of course. XD
A Swordsman needs to have melee attacks, and defensive moves so they don't die. Healing helps too. A balanced swordsman is a good solo class in some areas.

The Ranger- The Ranger focuses on ranged attacks. Arrows, Guns, etc. They aren't very tough though, and need to stand back to be effective.

The Ninja- Ninjas are quite fragile. Their main strengths lie in avoiding attacks, and hitting back, hard. Obviously, the Ninja Ring set is very useful here. XD

The Mezzer- The Mezzer focuses on buffs and debuffs. They're a support class, and useful for bosses. This is a build to use sparingly.

The Jack- Jack of all trades, master of none. Jacks tend to have aspects of several archetypes. As such, they're great for soloing. In a group setting however, they're less useful.




Solo Vs. Group Play
What rings you prefer to use depend on your play style.
In a Solo Setting, The "Jack" archetype is quite useful. You can deal damage, and support yourself. However, when fighting against difficult enemies such as bosses, a group setting is often needed.

In a group, you need to specialize, taking a role that will assist the group as a whole. The classic three person group is "Tank, Healer, Nuker", with other classes added on as needed. Once again, you are free to do as you please.

Remember, the Smart Gaian doesn't stick to one build.
It's a good idea to have at least two builds: One for Solo Play, and a more specialized role for a Crew setting.

Using Ring sets-
Ring sets offer bonuses to stats if the rings are placed on the same hand. These stat boosts are very useful. When building a class, consider using a Ring Set for the stat bonus, especially if the ring fits into the archetype or character you're aiming for.

Hybrid Classes-
Don't feel like you need to be anchored to one archtype. With 8 rings, you can focus on one role for each hand. (I.E. One hand for Tanking, one for Nuking. Or one for Melee and one for healing.)
Be creative!




Useful Rings for any situation
Divinity- Good for recovering Exhaustion.
A Self Healing Ring- Perfect for soloing.
Buddy Call- Not so good for a party setting, but it's nice to have this ring around. Also good for calling someone back to your location after they leave the null chamber.
Defib- At least one player should always have this in any crew setting. Always. XD Other players with extra ring slots should fill them with Defib as well.