nocturne; farm and don't gank without ult unless you know you can get kills/assists
From all my games as nocturne through out the seasons, I have learnt one thing that is essential to his playstyle.
Nocturne snowballs with how well the team is doing by themselves.
If your team is performing well, you will be a power house in team fights. You can 1v2 their bot lane by ulting in and if the enemy team uses all their cc on you to kill you, your team will dominate that fight
If your team is performing badly, you can't do anything but ward and pick off people running around solo
This applies to laning phase as well. If your team is doing well and they can make your ganks work by getting kills, you are rewarded tremendously. If you ult into a lane and you get nothing from it, you lost a bunch of time, gold and experience (and now, stacks on the feral flare). You also put your ultimate on a 3 minute cooldown.
There is nothing more useless than an underfarmed nocturne. You are useless. Absolutely useless. I can't emphasise that enough.
Absolutely useless.