Riven is mainly a solo-top champ, with one of the strongest lvl 1 damage thanks to his passive, and so much maneuverability its crazy.
She is the type of champ to take on 1v2 lanes easy, you just need patience and skill, to wait for that jungler and strike at the precise moment.

Ive looked around moba, and i havent seen this build in it, so i decided to upload it.
It should be a classic

Wriggle's Lantern
Good for early damage, lifesteal to farm, and a free ward every 3 minutes to keep yourself safe from that enemy jungler. i usually skip upgrading to wriggles when i am doing really good.
buy and early madreds razor and then get a phage.

Mercury Treads
Main reason for buying these sneaks, is Tenacity magic resist is also useful.

Frozen Mallet
The perfect item for riven,its an instant exhaust, the slow will ensure 3x damage.

Atmas Impaler
A must have for riven, armor, ad, critical.

Guardians Angel
Armor and magic resist boost, and the resurrection will bring you up and you can stun anything around you and escape with your Q

Everything else is optional.