Sorry my english guys, but im brazilian, and this is not my native language.

I've played a lot with this melee champion, and his "squishy" im early game may unbalance all the team strategie. The common Nocturne player, always run in a DPS + AD build, making dps boots, and after, the phanton dancer.

This strategie is not wrong, but risky. The passive came every 10 seconds, but you can't count always with that. So, in a few words, you MUST do some damage, and survive in first stage of build construction. In second, you build you "tank structure", an finnaly, the speed.

Again, sorry my english, and lets see this review.

The item purchase, show just the final...

In early game, um must have Doran'shield and Wrigle's lantern. This 2 itens will gonna be the key for your survivability. With this 2 itens, run for Frozen Mallet, and after, Warmog with atma's combo. Sell Doran'shield and Wrigle's lantern, and run for Bloodthrister, and for final item, Black Cleaver (the DPS you need, trust me), or Banshee's veil.

Remember, the ultimate can be used for attack or for defense. Use it with the certain of kill. Wasted Paranoia is lame for Nocturne and for you. Study the range (try looking at minimap, to get some references).
Shroud of Darkness is the banshee's abilty from Nocturne (use against Karthus's ult, works), and the passive, will help you in level 18 with your DPS (added with Black Cleaver, will crush tanks and Off tanks).

Clairvoiance is for PARANOIA.