Know when to fight, know when to run.
The key to kills, getting the edge on people (goldwise), fight on the dusktrail. Its like from starwars "fight from the highground" - obiwan kanobi to anakin skywalker/vader - A good opponent will not fight on the dusktrail, they will run, wait for it to clear, and mana drain you (like a fury char, renek or tryn), or rush back in in the 6 -10 second period when its on cd).
p.s. first noc build, my origonal, second, the one im currently playing, third, my dominion noc.

In dominion, I dont suggest spending much time on jungling. The key is teamwork, staying active, winning small battles and the big battle at the windmill. It should be 1 defending bot, pref a tank or heimer, 1 defending middle, 3 top. If you have smart teammates they will keep one person at each station but I often find 3 top and 2 bot and middle open, which in a game with a stealth like twitch or any smart person, that base will get taken and cause problems. Dominion is alot like arathi basin if your a wow player, all about teamwork, staying mobile and keeping a lookout on whats happening. Minions are lucrative, but you can lose a game by minioning, do it but dont overdo it.

I find that the key to having more wins than losses, is to play premades with good teammates. I do alot of randoming to find good teammates, I go through and delete players everynow and then, thinning the flock for pros etc.
A winner is a blend of a good gamer, a good champ and a good build (skills, items, glyphs).
When you can influence your teammates, go for another cc character like fiddle, another assasin, like shaco, another tank like rammus (i like to go merc/ninja, sunfire, mogs, nature/thornmail (depending if its 1 melee 2 casters, or hybrids, or 2 melee 1 caster)). I find that the CC characters are the easiest to rape 3's with.

This build is an all around build I have been using on multiple characters, I simply choose to do the build with Noc because he blends with build. I generally use the same masteries/skills/runes on all melee/jungler characters, replacing the bloodthirster for a phantom dancer will do wonders if you want to try a crit build (also if you do this, switch the black cleaver with infinity edge in item sequence).

In keeping it short and simple, why I like this build is because you can tank towers late game, full health refill off one enemy minion wave (or roughly 500-1500 off the jungle minions), well rounded defense, semi good get away/initiate (duskbringer, exhaust, ghost), excellent gank and survivability.

Pros

Well rounded build
Heavy hitter
Has fear
Quick life regen
Long range attack
Can block some killer ults, exp, caits, lux, nunu's ult.

Cons

Squishy if cant minion feed
Often targeted for ganks
Not the best at escaping

Lesson #1 grasshopper: Minons are fri-enemies. In 3v3, each wave of minions is 1/2 of a player kill, if you can get last hit on all that is. The trick is not to overuse your duskbringer much when minioning because of nocs low mana pool, it does good aoe, but if your not in the right spot, it will result in losing many minion last hits. Early game is about how you did on the first gank (or fail gank) and minion kills until lvl 6. Any good game will have under 5 total deaths before lvl 6 and low death count until about 15-20 minutes into game, this means the majority of the game is jungling and early game to determine how late game will be played.

Remember potions early game. Baddies wont get them, remmeber to target them, and memorize each summoners spells and keep a mental note of when they use em so you can add that into your plans for ganks.
The basis of this game is teamwork. Be careful when only one or two of their team is visible on mam when you are traveling to gank, exp, running into 3 ppl in a bush above where your two teammates are).I like to get to lvl 3, or 6 before doing gank on 2 people.

Tower hugging: if your in a 5v5 and your teammate is out jungling, you will have to tower hug for a while, potions and life steal while hovering under your turret will help you survive until help arrives.

Another thing, you dont want to spend too much time waiting on ganks though, remember that minions are half or more of the gold earned in the game. Time is money, and you better farm minions!

Be careful when you see an enemy run out of a bush, use one spell, then run back in. Its called baiting and one or two other enemies are in bush, either than or its a bluff, to scare you off so you wont come into the bush, possibly they are doing red, blue, dragon, baron buff etc etc. Use duskbringer and listen if it hits anything (you can hear it collide if you have good speakers).

A smart team talks alot, pings alot, and coordinates baits and ganks. Have alot of friends on your contact list, and a smart gamer would have ventrilo, then let the wins roll in.

It seems like common sense, but monster level scales with your level, so if you bought the vamp sceptre first, yo could do jungling at lvl 1. I never thought about doing this, but I seen characters doing it. Idk, people over 300+ wins do it, people under 300 wins dont.

I prefer to top lane in 3v3 and top lane in 5v5, this allows for faster utility of lvl/18 runes and also if you decide to start juggling to gain kills. I like to get to wriggles before I start to venture into the jungle though, you can start from lvl 1 if you want to get potions (if you do jungle immediatly, start with cloth armor and some potions or vamp ring)

Jungle, jungle, jungle. Hit "O" often and check up on enemy minion kills, 10 is roughly 300 gold (or less if they are jungling the tiny minions), take this into account with each kill is 300, plus 150 per assist (more than generous, which is to compensate for the gold per hour rate), if you have the edge on gold, and its spent, and you have the edge on minions, you can kill that person in 1v1 combat easily. FIGHT ON THE DUSKTRAIL, it is what completes the build and gives noc rape early game,allowing for late game rape.

I have been playing this same build alot lately, usually I play 1-3 games a day and I win 2 to 3 of them (im on a 10 win streak with build, 9 times noc, once as twitch). I have modified the rune build a little bit from what I origonally had to give it all around help but leaning towards damage.

6 armor penetration marks
3 critical chance marks

6 damage/18 levels seals
3 hp per/18 lvl seals

3 damage/18 lvl glyphs
3 flat magic resist glyphs
3 attack speed glyphs

damage/18 lvl quint
attack speed quint
critical strike quint

this gives you better end game damage and more of an edge when your higher level than them. The attackspeed is for when you are level 3 and have berserker boots, your attackspeed should be around 1.0 which is enough to win battles and get last hits, its enough to suffice until about level 9-12 when your geting black cleaver and leveling up shroud.

I choose the lvl/18 runes because it gives nocturne better survivability in mid and late game.
I also choose the stat + per lvl/18 because any good game will easily go 30 minutes and if you minion farm well, which is they key to any good game, you will have the advantage then and at final late game (Ragnarok as I call it. lol, jk i never call it that, just made it up)

Other viable options-
all attack speed runes + shroud of darkness + dagger. Use ghost and exhaust to focus an enemy, also allows for quick last hitting minions early game, If you go this route i suggest getting duskbringer next, then berserker boots, keep rest of build. I find this build is good vs a heavy melee team with no need for the tenacity or magic resist.

all flat damage runes + health quints
I always prefer to keep the quints, having the extra health bar makes you seem intimidating, along with long range duskbringer enemies will let you minion feed early game.

One slight alteration to the mastery build I gave, 4 alacricy 2 offensive mastery. This allows one more for possibly getting ignite, if you like ignite better than exhaust (although exhaust works better with duskbringers enhanced move speed buff) or another 1% cooldown reduction.

defensive mastery build?
Good for first gank survivability, I wouldnt suggest it but if you do try, go for the usual tank build, omitting dodge mastery.

Utility build:
If you choose to go with utility, get youmuu's instead of black cleaver, and flash/ghost for better surviability (which is the only reason I can see someone going utility on an assasin toon like Noc)

The dorians can be switched out when buying the frozen mallet's giants belt, after you have completed the black cleaver or later in game if you feel the need.

Other viable options for replacing wriggles lantern late late game
executioners calling
hextech revolver
starks

I prefer to always get duskbringer maxed first, it allows me to escape or initiate, get move speed to chase and get in range to fear, to get past minions, to farm minions early game etc.
the downside of this, is when you play a really good player who has leech and avoids fighting you on your duskbringer. Or a player like tryn that can avoid ur duskbringer quickly and down you on mana. If they have a spell they cast on you, you can build shroud first and use that to attackspeed kill them. Whatever your strategy, remember to fight from the high ground.

I prefer ghost and exhaust, both are beneficiail to my origonal mastery build and my duskbringer. Flash can also be used but I have found it less handy than ghost.
Clairvoyance is a good spell, im unsure of how good the mana spell would be on noc, I never vary from exhaust/ghost.