Hell-0!I'm Regiel and these are a few of my Dominion Builds that will make sure you will win.
They can be combined together as a team were Evelynn is the main damage Source, Rammus is the Utility/Assasin and Hecarimis the tanky Compadre.
These Builds may look very stranger but belive me,they are all battle tested and their effectiveness is more than surprising.
The build is based on mowement speed throughout buying Phantom Dancers and building your Runes and masteries around mowementspeed and Crit/AD6Attackspeed just to make those Phantom Dancers have their use also you buy Lifesteal because you will mostly sustain yourself by gaining health back to avoid quick death in a teamfight.You vuy no HP MANA oranything like this(Only with Hecarim and Evelynn)So you have to gain those stats from masteries and runes.
Why is this build good?Because your high mobility will allow your team to get to every point nearly instantly.from the very beginning of the game you all have the most mowement speed and if all three of you goes to the windmill than you will capture it before the enemy has a chance to touch it.Also in midgame you will be the perfect assasin and in lategame(if you dont win earlier) you are immortal(dealing 800 damage a second with 20% lifesteal is not a good thing to the enemy)But be careful!You are not so capable at earlygame in teamfights if you are alone with this build!If you have all 3 of these champions in your team and you have an AP who is not a glasscannon( Kennen for example)and a tank who takes bot IT IS IMPOSSIBLE TO LOSE.

I DONT ADVISE YOU TO TRY THEM IN 5 V 5 OR 3 V 3!!!!

The items are The Core.they make this 3 champion the kings of Dominion.the high mowementspeed and crit/AS combo is a lethal secret that now i give away.Open your Ears because this build will change your life if you are skilled enough to use it.
The main item is Zeal after buying a fast boot(Swiftness or Mobility its Up to you) and your Trinity Force, if you are Evelynn or Hecarim. you begin to fill you slots with Zeals only(Its important to buy a Vampiric Scepter after the first or the second) than when you are complete and filled your remaining slots with Zeals and Lifesteal you begin to upgrade Zeals to Phantom Dancers(expect when you are Hecarim, than you buy Phantoms instantly as shown at item purchases).usually the match ends somwhere around your last Zeal or after your first PhantomDancer( i only finished the build 4 or 5 times because we won earlier).
Evelynn] needs [[Trinity Force because when you stack a critical with shen than it deals 400% of your base AD that is a kinda good combo with your 2.28 attackspeed.
i buy Hecarim A Trinity Force because it gives kinda good HP and manaboost.also Sheen stacks well with your Q so it also leads you to 400% damage and you gain a kinda high AD from mowementspeed.

The Skill Sequence is one of the most important parts of this build next to items.They seem illogical for normal gameplay...and you are right, they are useless for normal gameplay but for this build they are necessary for instant and total domination, and i will give my reasons:
For Evelyn:
MAxing your Shadow Walk is for allowing you to sneak trough any enemy, your main goal is to assault the enemies farther Capture points, this way they will be forced to retreat from assaulting your capture points to defend theirs.You max Ravage second to have a nice armor and MR Reduction that is very good for initiating and you will be allowed to take out tanks less than a 5 seconds without buying further Armorpenetration.Your Hate Spike is the key ability of your build so put a point early(lvl 4), if you capture windmill(You will) than you lvl up to 4 right before you encounter any enemies. Hate Spike is the main source of your damage because it will activate your Sheen every time you use it that leads you to 400% critical strikes.This is why it is important to keep it at low skillLvL.This way you keep it at low manacost.use your Agony's Embrace as an initiating tool and make sure you slay a foe before it ends so you can survive even 2 v 1 fights with more than 50% HP.Also if you combine your ultimate with Surge you are close to Immortality if you have something to hit.
Rammus:
Your Key spell is Powerball but you should keep it at low skill lvl because its important for traveling and neither its cooldown nor its speedboost incrases by LvLing it up.Also its a very good distruptive tool/escapetool/initiateingtool.Your Defensive Ball Curl is very important!Combine it with taunt against any physical damage dealer but against AP casters i advise you to activate it only after taunt ends this way you can avoid more damage(if they survive your strikes,that is not evident).It gives you a lot of armor that gives you a lot of AD that leads you to extra high Critical strikes!Your Taunt is also very important.The main tactic is to charge the enemy with Powerball and Taunt him before he has time to cast any spells,Right after taunt ends, pop your Defensive Ball Curl so if the enemy is still alive(i doubt) you still recieve bamage below 100 :D.this way Rammus is a very good Surprise-buttsex assasin who is very good at preventing a sole enemy from capturing points.Your ultimate can help you in teamfights and pointdefense but it has not much use at all but annoy the hell out of the enemy
Hecarim:
Because you need extra high mowementspeed for reaching points in seconds i advise you to max your Devastating Charge First.this way you can catch Up to Rammus and help him dealing with foes.2 of you are a very good combo.I dont advise you to max Rampage because you are more tanky and you deal most of your damage with basic attacks but its very good for popping your Sheen so keeping it at low manacost is a very wise decision.Your Health regain is very good with Spirit of Dread, also you help your team deal a few Aoe Damage that you are lack of so i advise you to max it second or next to Rampage.Your ultimate is very good for initiating with Rammus and Evelynn, or to defend points.While they are feared Evelynn can take out any sole 1 and Rammus can taunt those who have CC source also you do ****loads of damage with your basic attacks so you can even do a pentakill from a 3 v 5 encounter

The Runes are chosen For this special mowement speed style.The goal is to juice out as many stats that you won't get throughout items/need early boost as possible.You take mowement Quintessences with all three champions for the main reason of point capturing.
With Evelyn:
Get every source of damage for being more effective at earlygame.You need a bit of Attack Speed boost and early Critchance also that flat AD is also very handful.I think that its simple to understand.(you stack Sheen with Hate Spike and all of them will be a 400% basic attack beacause of crit and doubledamagesheenbuff...i cant stop repeating this)
With Rammus:
Armor is obvious.You need sustain and it also gives you nice AD that is a very good combo with that flat attackspeed that you've also got.You need crit damage because you dont have to buy Trinity Force so you will have high crit chance earlier than the others that will make you deal some nice juicy crits
With Hecarim:
Mowementspeed Quints are evident:They also give you some AD so its a perfect choice.You must be the Great Column of this Triumvirate,you are the "tanky" one so i advise you to get a lot of HP/LvL runes so you wont have to care with health from items.Armor penetration is for strenghtening you at defeating higher defense enemies and it also boosts you abilities but you may consider flat AD instead if you'd like to

Masteries are built around different goals for the different champs but all of them gives armorpenetration and mowementspeed also mana/lvl to make mana buying unnecessary at early LvLs(you'll get enough mana with all 3 of them)
i give Evelynn more physical damage because she is the main damage dealer assasin who may appear everywhere
I give Rammus armor for AD and A little HP boost to make him avoid being such a Glasscannon.
With Hecarim i create the perfect balance.i take Armor pen AD and Attackspeed also High Durability and utility throughout his masteries.He is the most Mobile of the 3 champions.

Summoner Spells are Evident.
i take Ghost for everyone for the one sole reason of capturing Windmill early and get to points fast during the entire game. Hecarim also can use it for initiating with higher AD
With Evelynn, your second spell must be Surge.For giving your Hate Spike a slight higher Damage and to do Criticals more often.its the best combo with Agony's Embrace.
The others may take anything but i advise Exhaust or Ignite for dueling or avoiding tight situations but you may also consider Flash or Heal

VERY IMPORTANT!

Now i describe a bit of my strategy that makes this 3 champions PWNlords in Dominion.

When the game begins Take Boots Immediately and get your mowement incraisng skill if you have 1(you can see at skillsequence)
When the Game starts all 3 of you MUST pop Ghost also Rammus activates Powerball, Hecarim activates Devastating Charge and Evelynn Turns invisible.this way it takes around 20 seconds to get to the Windmill and capture it.If the enemy has fast champions( Master Yi, Rammus, Hecarim, Teemo...) send Evelynn to the fog of war to scout them, otherwise make her capture with you.the 4th member of the team( Kennen for example) captures your first point and the 5th member(a magic damage tank or hybrid) goes solo down.This way YOU MUST HAVE WINDmILL BEFORE THE ENEMY APPROACHES.Otherwise you did something awesomely wrong.After the enemy appears dont fear to use all your summonerspells to defeat them.focus the 1 with the most capable CCs or Damage.You have a weak earlygame so you'll need the point-turret and your summoner spells but use them!The enemy wont use his summoner spells necessarly for keeping it avileable.if you can win the first fight and more than 2 enemy dies(and all of you are alive) than push to their next point and make sure to farm some minions.When you are done go back instantly and buy your second item ( Zeal Sheen or Phage, depending on champ)
Evelynn should always try to capture the farthest points for separating the enemy. Rammus and Hecarim can go togther and land surprise assaults to capturing and/or Defending enemies.One of your main elements are the Surprise attack, you can deal ****loads of damage faster than the enemy can react to your approach.
Rammus: Charge with Powerball> Taunt>pop Defensive Ball Curl while Hecarim charges and pushes back the one who Rammus didnt taunted.After this finish the taunted one who has nearly half HP after Rammus attacked him and Hecarim popped his AoE spells.After this you can easily finish the other with a 2 v 1 overrun.Always focus the 1 who can stun or fear.Silence is useless against you.if they have heal reduction you may consider focuing that 1 because lifesteal is the main sustain of the build.
Evelynn should always seek for even fights or low HP enemies and take out the potent targets.Her 400% basic attacks stack very good with her lifesteal.

Pros:

+Fast point capturing
+Perfect surprise attacks
+ good damage(400% crits)
+ good mobility at every situations
+ Fair HP with high damage and lifesteal sustain
+Perfect group for teamplays
+Loading screen totally distrupts the enemy team
+good Initiate/chase/flee
+Perfect Duelists

Cons:

-Very sensitive to CCs
-Nukers are very dangerous
-If the enemy initiates its very hard to win the encounter
-Alterego champions can kill you(Expect Rammus)

Rammus vs Dominion Rammus(+)
Dominion rammus VS Hecarim(+)
D Hecarim vs Hecarim(-)
D Hecarim VS AP evelyn(-)
D Evelyn Against AP Evelyn(Depends on initiate)
D Evelyn vs HEcarim/Rammus(+)

-The team may misunderstand and flame you
-Needs a lot of gold
-poor at defending alone
-Weak early teamfight capability

So this was my Dominion Guide for 100% win.Remember to care about CCs and to ambush the enemy from fog of war or from stealth.CAPTURE CAPTURE CAPTURE!
GL HF!
I hope you'll like it!