Welcome to my first guide! I play Nocturne as a physical dps carry. He's relatively squishy so positioning and knowing your strength vs the enemy is key. You may want to consider different builds if you need more hp to play melee characters. Also, he's probably going to be nerfed but atm (3-21-2011) he's very strong early/mid game and continues to crank out the dps late game.

Pretty standard physical dps runes here. Armor seals for early jungling can be swapped with dodge seals (personal preference).

Again pretty standard jungle items to start off with.

Boots:
Mercury treads are the only other real option for Nocturne. Make your boot decision based on the opposite team. 3 or more CC on the other team = Merc treads.

Wriggle's Lantern is great! The lifesteal and free ward are incredible for the price.

The rest of the build focuses on dmg/attack speed and some survivability with Banshee's veil.

You can start laying on the hurt big time once you have B.F. Sword and Zeal.

Late game you can replace Wriggle's with Bloodthirster.

Dusk Bringer is your bread and butter early game so max this first (1st point in shroud of darkness for the passive attack speed is crucial though).

Follow up with Unspeakable Horror for some great CC and ganking opportunity, and then fill it out with Shroud of Darkness.

Smite is required for jungling.

Secondary skill is personal preference really with ghost being my choice. Flash, ignite, and exhaust are other good options.

Nocturne is a great jungling character. His ultimate is awesome for surprising characters that push too far, chasing/finishing, or teleporting to team fights / turrets in trouble.

A note on ganking:
1. Try to have red buff
2. It's hard to land Duskbringer from bushes sometimes so try popping ghost (or just running behind them) to close the gap and then use Duskbringer when they have chosen an escape path.
3. You don't always have to use your ult to gank!

Late game:
Many characters will have BV by now. Since most of your damage should be coming from auto attacks, use Duskbringer to pop their shield and then Unspeakable horror to CC.

Thanks for reading my first guide! Happy hunting :)
TkG Mars