Well, I'm Heres Daddy. As of the creation of this guide, I am a Gold V Riven Main on the NA server. I've been playing Riven since early-mid Season 5. I know, that's not impressive or anything, but I felt like what is in this guide needed to be pointed out. I'll go into ranked games and see Riven players pick into bad match ups or build like garbage, and of course they end up feeding their butts off. I felt like maybe something like this from one of their fellow lower ranked players could assist in my wish of seeing decent Riven players in this ELO.

This is a guide on how to play Heavy AD Riven. Many people find themselves ineffective in games on Riven when they build a lot of damage. More often than not, it's because their build lacks one or more important components of a good Riven Build. A Good Riven Build should provide the following: Decent Burst Damage, Some kind of Survivability, Potential to Snowball, 40% CDR, Lifesteal, and Late Game Viability. While Riven is primarily strong in the early-mid game, she can be just fine in the late game if the player's build contains the previously mentioned components.

While Riven certainly isn't in the best of spots right now, she holds a place in me and many others' hearts. She provides insane roaming potential with multiple instances of crowd control and mobility. Her outplay potential is immense with her CC, mobility, and Execute Damage Ultimate. These things along with the fact that she can animation cancel her way to victory earns her my spot as favorite top lane champion, easily.

Youmuu's Ghostblade provides most of the stats Riven will need for the early-mid game in the form of Movement Speed on the active, Damage, Armor Penetration, and Cooldown Reduction.
Ravenous Hydra provides access to the Tiamat Active ability, which is an auto attack cancel! This is insane on Riven in itself. Don't even mention the fact that it makes all of Riven's Lifesteal apply to the AOE on-hit cleave.
CDR Boots are just great on Riven. They're better than any others in this build because of the reduced summoner spell cooldowns and the base CDR they provide for only 900 Gold!
Death's Dance Provides the ability to survive burst damage with the damage reduction passive. It also synergizes well with Riven's absurd amount of AOE physical damage.
This item.. You can place it in this build if the burst damage on the enemy team is too much but you don't want a GA just yet. If you're gonna build it, build it after hydra and before DD.
Buy this after DD almost always. You'll fall off in fights without it. Doesn't take much for the enemy team to focus you down with some CC.
You can buy this or just the QSS if the enemy team has something irritating like a Malzahar.
As long as you keep auto attacking, this item can quickly run you out of control in team fights. Unless they can burst you down, how are they going to kill a Riven life stealing half of her HP every auto? XD
On very rare occasions, I will have to build this item in this build. It's when you really need health and armor but also some kind of damage, all in one item. It will replace GA or DD if you do choose to build it.