Note: The raw information come from Fantasy Earth Zero Forum, thanks to Blazenarm's sharing.

Prefight

Starting out

First of all, all zones show how many people are in it when you're on the map. Watch these closely, especially around enemy territory. Keep in mind that in order to declare war, you actually have to have enough people to start. When you get in a territory, ask if anybody is already heading somewhere to declare war, then start grouping up with 'em if they are.

Also, if joining a battle late, check how many people are fighting. Some people don't like to play in a full 50v50 field. (This guide is more about the players who are in the fray from the start, but the strategies herein can still be utilized).

Keep

Don't just run off randomly, slap down a keep where you think it's feng shui, and expect people to love you for it. ALWAYS confer with other players before placing a Keep, it's just good taste. Some factors to consider when deciding where a keep should go:

1. Crystals. No DUR! Usually maps will have a spot where you can build the Keep in between 2 crystals and be in good shape. Always a solid strategy, but can be overlooked in some cases.
2. High ground. It's your friend vs Chimeras. You will be lovin' the long routes Chimeras will have to take just to even see your keep on some maps if you place it right, because A. It gives you more time to spot one and B. More time to kill it with FIRE!
3. Bottlenecks. Oh yes, the bottlenecks. Get a good map, place a keep where the only access to it is maybe 2 STEEP canyons, build two Bulwarks, and lulz ensue.

What you should do after the declaration

Call out what SPECIFICALLY you plan to do. Preferably choose something you know about. I.E. EVERY fight needs miners and builders. If you don't mine, you don't build, and if you don't build, you lose. Period. Even if you are a gaming god. Basically, 2-5 Miners at a crystal is good, with one Bank. If you claim the job of being a bank, then BE A BANK.

Do NOT take the crystals everybody's farming then run off screaming into a mob of enemies only to die and waste time and lose crystals. Trust me, that's not a good way to make friends. If you're a miner, HEAL before you start mining. Yes, the crystal DOES heal you, but it drains it even faster. Once you have builder (Obelisks and Summon Related buildings at first, please) and miner assignments decided, choose a group of people to be the Summoners. Preferably, Builders and Miners should party with each other, and Summoners should party with other Summoners. Just makes things easier, ya' dig? (PS - I know, you have a lot of HP when you Summon, but if you Summon and try to lone wolf it out there, that HP will go. Probably pretty quick too.) (PPS - If you DO see 10-20 miners at crystal, just go away.)

Beginning of War

Priorities

Obelisks. OBELISKS. obelisks. Oh, did I mention Obelisks? Because yeah, Obelisks. If you don't start grabbing up that territory, it's gonna bite you in the rear later on. More territory = more damage = faster win. However, not every person should be running around in circles building Obelisks (at least 2 though, I mean, come on), and there are some do's and dont's with building them. DO place on edges of your territory. DON'T put 5 right beside your Keep to make it look pretty. DO build them in relatively hard to access areas, such as on a cliff (where your teammates can knock players off said cliff if they're attacking it). DON'T build them in front of a wave of enemies. Especially Giants. Just don't! DO space them well and preferably build a few Arrow Towers to harass enemies trying to kill your best friends. (The Obelisks = Best Friends)

On the flip side. KILL THEIR OBELISKS! Their Obelisks murdered your friend, insulted your mother, and kicked your dog, then tea-bagged you because they could. They are MEAN and deserve to die a flaming death. You should go out of your way to destroy them because A. It hurts their Keep, and B. It keeps it from hurting your Keep.

Try not to die. Especially if you're a miner/builder/banker. I know, sounds obvious, but those who use crystals should especially not die, because you lose 3 every time you die. And that's, well, just no good.

War Workshops / Gates of Hades -- These should be a priority ONLY if you are going to have somebody actually using them. If nobody uses them, congrats! You just chucked 40 crystals away! You so leet!

Strategies

If you summon anything other than a Knight or a Dragon, get two Knights to accompany you. Why? Oh let's see: A. Giants. My grandmother could sleepwalk backwards faster. While wearing a lead vest. You're gonna want some Knights to protect you in case of enemy Knights. One Knight v one Giant = dead Giant /weep. B. Wraith. Seriously, do you LIKE tossing away 50 crystals? Are you so rich in crystals you can make it rain (crystals)? [...sounds painful. If you can, refrain from doing so please] C. Chimera. A monster that can DECIMATE the enemy keep, and you wanna let 30 odd players use it as a punching bag? Yeaaaaahhhhh...no.

If you have a knockback skill, and you see two enemy Giants (or similar) coming to you, you can SINGLEHANDEDLY halt their advance if you play your cards right. I suggest doing so. People will love you. Name their children after you. That sort of thing.

Call out enemy locations, priorities being Chimeras, Dragons, Giants, Wraiths, Obelisks, Knights, players. In that order. An ounce of prevention is worth a ton of monster fury not being forced down your throat.

Group up with other classes. Be a friend to somebody stranded and getting tag-teamed. Don't do stupid things. All the common sense stuff goes here.

Don't zerg rush. It won't work on here. Go ahead, try.

You can build while having a summon up. Best use of this is the Knight (for it's speed) and using it in conjunction with Miners/Bankers in order to quickly build a lot of Obelisks and solidify your territory. [Credit for this tip goes to: Sreya]

In trouble? (Alt name = Oh noez!)

Chimera

Eheh. Eheheheheh. EHEHEHEHEH! First time I saw what one of these babies could do, I cried. Because it did it to me. These horrible (or freakishly awesome, depending on what side it's on) can reduce the HP of the opposing Keep by a third of the total HP {read: one entire bar = 30,000 damage} and pretty much kills every single player that is unfortunate enough to be near the Keep. (Credit: Winged139). Downsides? Slow. 40 crystal summon. Requires an item {Chimera Blood}. Continuously takes damage over time. You can only summon once your Morale drops to the second and third bars, at a rate of once per bar. And the biggest drawback is that it actually needs to reach the enemy Keep to do what it does best.

Dragon

Uh, did you even TRY the tutorial? If so, you know what's up. The main strength of this is that it's FAST. Really fast. Oh, and it can fly too. Does pretty much the same damage on all targets, be it summons, players, or buildings. Downsides? You have to die under certain conditions. And it requires an item. (I haven't been successful in summoning one yet cause I can't find another Dragon Soul other than the one you get from the Yellow Letter quest, which I promptly turned in for 40K gold and a ti.tle). And you have to be losing.

EDIT: To summon a dragon, you must be losing by quite a bit, then die. Your Dragon Soul must be in your inventory when you die, and from there on it's a random low chance to summon a dragon.

TURTLE!

If you thought this was a summon, exit your browser and uninstall your game please. I'm referring to the last ditch strategy known as turtling (Think of a turtle, what does it do when it's in danger? Recedes into it's shell). Basically, build Bulwarks in major areas, huddle around the keep, and fight to your last breath. Haven't actually seen a War where things got this bad yet, but it's bound to happen. Here's what you should do: Warriors/Dagger Scouts up front. Create mayhem while you have Sorcerers freezing and Bow Scouts knocking back, while other rangers fill them full with holes and then cram fire in said holes.

Quick Note: All of this come from Blazenarm's ingame experience, thanks again for such cool effort.