Intro to Exile
This build is to ensure that Riven is given the max damage possible when laning. Stay back and wait for lvl 3 to go in and attack enemies. Riven is an expert at getting away using her skills. This is the best build i have found for her and i have always come out on top.
I normally take 28-0-2 in masteries to optimize Riven's merciless attacks. Building an offence early in the game will tremendously help in leading the game in kills. The two in utility are just for the flash to get away if need be and a fast recall so you can hurry and buy items.
For items i start out with the Doran's blade. Stay in lane as long as you can to put pressure on the enemy champions so you farm the minions and they don't. Killing as many enemies as you can with a doran's blade is helpful. This allows you to save up for the BF sword you will need for the Black cleaver. after that is acquired, the rest should be easy. Riven is naturally fast so getting boots will help chase down enemies extremely easy. After the Black Cleaver, immediately go into phantom dancer. The speed will help make killing a piece of cake. Upgrade to boots of swiftness at any time. If the game goes on longer than expected, you might want to look into getting infinity edge. Stacking on phantom dancer helps. Then for overkill, get another Black Cleaver if you can.
The first skill should always be broken wings. It provides a great way to escape and poke at enemies in the lane. Second, get the ki burst. Stun the target and continue to poke at them. Third, get Valor and jab at enemies in lane. Valor in at a target, stun, then open up the broken wings on them. Of course at 6, get the Ultimate. As soon as you get your ulti, max broken wings. Being your gighest damage output, having that will increase the kills dramatically. Then work on maxing them in order, ki burst, then valor.
I personally don't use runes due to the low amount of IP. But build on armor penetration, attack damage and some health regeneration. Concentrate on attack damage as much as possible.
I use teleport and flash for my masteries. Flash will help you get even closer to catching fast enemies when combined with valor. The teleport allows you to go even quicker to allies to either help or to go farming.
Creeping / Jungling
Whenever you get the Black cleaver (lvl 9 or 10), you can easily get golem buffs. Getting the lizard buff will always help with Riven. When the phantom dancer is acquired you can easily solo dragon. After that, just keep getting the items i've laid out and baron will be all that easier for your team.
Riven plays a big role in laning. With her stun and massive damage output, you and your laning partner can easily take down an enemy. You always want to Valor in and stun them so they don't have a chance to react. Stacking stuns upon stuns, it gives both you and an ally time to wear down the opponents health. When your enemies are low, use your stun to stop them from getting an unwanted kill. After early aggression, the rest will be easy with your items.
Whenever you use an attack, Riven gets a stack to increase the next attack. After you stun, them broken wings (1), wait for a basic attack to get the stack. Then broken wings again, basic attack and so on. Each time you reach the 3rd stack, it resets with a skill. When you get your ulti, it is best to try and use it on the thirt stack to optomize total damage output. The items will completely obliterate any opponent in your way.
farming is a walk in the park. Valor in like you would a 1-1 and stun the minions. Then use broken wings quickly without the basic attacks. You can easily take down mounds of minions just by using the broken wings, but extra damage doesn't help either.
Pros / Cons
The pro's to Riven are her massive damage output late game, her speed to catch enemies, poking ability terrifies enemies, decent health at start.
The con's are that you are slow early game and is somewhat squishy.
Riven is an all around DPS or AD character that is feared when she appears in lane. The cool-downs are extremely short and her ulti is less than a minuet long. Riven is very helpful in teem fight causing AOE damage with broken wings. A couple of skilled kills and you are set for the rest of the game. An aggressive Riven is extremely scary and no one will want to touch you. Riven is maximized for speed and power output on all enemies.