To understand how to play Twitch in Dominion it is first necessary to understand how to play Dominion. A game of Dominion is decided by a number of factors, most importantly: map control, number of captures and, to a much lesser extent of importance, kill count.

Capturing an enemy controlled point earns you roughly twice as much gold as killing the enemy defending it does. As such Dominion becomes less a game of killing the other team quickly and as much as possible and more a game of capturing points from you enemies while denying them yours.

Twitch fills a unique role in Dominion. He is among the best at interrupting an enemy team capturing a point and at stalling them from taking it. Yet, he struggles holding a point for very long by himself unless reinforcements arrive. He can easily slip behind enemy lines and neutralize points before they realize what is happening, however he has difficulty in completing the capture without support from his team if the opponents respond quickly. He can sneak around the middle of the map and reveal hiding enemies, but relies on support from his team to be effective in fights. He can easily take out most enemy champions in a 1v1 under the right circumstances, and as a stealth hero is free to pick his own battles, but dies extremely fast in a 2v1 or worse.

Twitch is not a well-rounded hero, and this build is not designed to make him such. He is extremely good at doing what he's supposed to do, and dies very quickly if he tries anything else. This build is designed to amplify what he is good at to the fullest, while wasting nothing on what he needn't bother with.

Pros:
-Can interrupt captures and stall a team from taking a point until help arrives
-Has incredibly fast movement speed that combined with his stealth makes him among the best at initiating a capture
-His ultimate turns his standard attack into a high-damaging area of effect which can slow down and seriously damage an entire team or everybody attacking a point.
-Can pick and choose his own fights and can kill or force a retreat against just about anyone in 1v1 combat, although it may require using his ultimate and summoner spells

Cons:
-Generally relies on a solid team to be effective and cannot by himself carry his team all the way to victory.
-Cannot hold a point under serious attack by himself.
-Has difficulty completing captures without support from his team.
-Dies very fast if focused in a team battle or in a 2v1 or worse.

Twitch, the horribly misunderstood rat, quickly became my favorite in Summoner's Rift after I purchased him, and since Dominion came out I've been playing mainly as him after realizing his talents transfer extremely well to the new game play.

What Twitch does in Dominion, simply, is everything other heroes can't do and don't expect. And he falls really short at attempting more conventional strategies.

To play Twitch with high effectiveness you need to be doing what the rest of your team absolutely should not be doing and may actively discourage you from doing. While the other 4 members of your team should be focused on capturing and holding a 3 point majority to ensure a victory, you should be off by yourself contesting unguarded points, ganking individual enemies in the middle of the map, and initiating attacks on groups of enemies by yourself to harass them, stall them, or interrupt them while they try to take a point.

You're also going to have a really weird looking build.

To start off the game you're going to want to buy Boots of Mobility, the ganker's best choice in footware. And you're going to want to head towards the top. How you get there boils down to two options. You can either capture the point nearest to you and catch up with the rest of the team once the battle for supremacy at the top has begun or is about to begin, or you can pop your invisibility, pop your Ghost, and rush all the way to the top and get there before anyone else can or even realizes that that is what you're doing. Your choice should reflect the enemy team's composition and what they're doing.

Once you get near the top, or immediately after you've captured it if you're able to, you're likely going to want to be cloaked in anticipation of the battle about to happen for control of it. Hopefully you put two points into this at the start, because you're going to want the extra time in stealth and you will almost always hit level 4 before you want to use Expunge.

Winning and surviving the battle for the top will leave you with a large amount of gold, map control, and great positioning. Allow your teammates to initiate the battle and soak up CC, then come out of stealth and immediately focus their squishiest Champions. You should be able to drop very squishy Champs with your auto-attack alone and save your Expunge for your next target. Note that even a few shots followed by Expunge and Ignite can kill most Champions, and there is no shame in using your Ignite this early since its an important battle. Do as much damage as you can, and run away and cloak as soon as attention turns towards you. Grab a health pack if necessary and come back out of stealth to finish off the rest of their team if anyone is left. Don't be afraid to KS, Twitch was made for it and other roles generally need gold less than you.

Once you've secured the top either B and buy a Zeal, or push another point with a teammate. Eventually you'll have to return and buy. Once you do, start roaming the map cloaked. Gank people in the middle, flank enemy attacks on your held positions, interrupt attacks on unguarded points and stall the advance until your team can arrive, and most importantly, initiate attacks on unguarded enemy positions. Even if you can only neutralize the point, you've done a great thing for your team (assuming that they can hold 3 points with 3 or 4 people), and made money. Then cloak quickly and retreat back to the middle, and restart your routine.

At first glance, this item build might seem very weird to use, even for Twitch. After all, it will have you buying four Phantom Dancers, which would be quite useless in Summoner's Rift. However, in the context of the unique gameplay of Dominion, this build can be highly effective.

Purchasing Boots of Mobility at the start will generally give you the fastest movement speed of anyone currently in the game. This will enable you to reach the top point before anyone else and either start capturing it or get in position for an attack, or to capture your team's closer top point and still have enough speed to catch up with them for the attack on the top.

Should you survive to capture both two points and the battle for control at the top, you will likely already have enough gold to buy your first Zeal. This will give you a boost to attack speed and critical chance that will help you stay a DPS powerhouse in the coming battles as well as giving you a bit of a boost to movement speed to help with your survivability.

By the time you've purchased your second Zeal this boost will have compounded to the point where you'll have a quite easy time slipping around enemy advancements and capturing unguarded points. Purchasing an Infinity Edge at this point will give you the boost to damage that you'll need to carry you throughout the rest of the game as the enemy team starts buying defensive items.

From here on you need only purchase more Zeals, the stacking bonuses from each granting you the ability to outrun everyone else in the game, easily escaping enemy responses to your captures, and with the boosts to attack speed, having the capability to slow, cripple or kill individual responders(or more, with your ultimate) before you dash out. If the length of the game permits, start upgrading your Zeals to Phantom Dancers. Remember that the more points you capture, the more gold you'll make, and the more effective you'll become at capturing them.

The skill sequence for Twitch in Dominion is quite similar to what most would use in Summoner's Rift. Max out your Expunge first, followed by your stealth, followed by your slow. The only difference is that you want to put two points in stealth at the start to give you more time invisible and because you will almost always hit Level 4 before you need to cast Expunge.

More on this later