Hello all,
Riven is a very mobile tanky DPS that is overall a lot of fun to play. She can get right up in the enemy's face and bust out a burst of damage in no time. A major key to playing her, however, is that you must take advantage of her strong early game. She can burst out a combo by level three taking down one of the lane oponents quite often, but if not done so carefully, you can over-commit to a fight and get stuck without her precious built-in escape spells. But when she gets going, she can stomp on any lane opponent.

I take armor penetration because it is by far the most effective damage early game that carries well into late game. It allows all or most of the opponent's armor to be ignored, adding maybe a 20% damage bonus to her early combo. Armor and MR are included to keep her from geting harrassed too hard. She is great when she can get up to her opponent, but if a Caitlin is simply harrassing from range, she can have a hard time. The armor lessens the effect, allowing Riven to get up close and personal much more effectively.

Even though Doran's Blade is the recomended starting item, I believe Doran's shiled complements Riven's play style more effectively because it allows you to regen health much faster. Riven is GOING to get harrassed, but a Doran's Shield lets you regen that harrassment much more efficiently.

Phage comes next for the health and damage boost. The slow is nice, but the tankyness allows you to take control of the lane. I have experimented with a Brutalizer and Riven is unable to get the damage off before having to retreat. The Phage balances offense with defense nicely.

Mercury Treads are an easy pick for one simple reason: CC WRECKS Riven entirely. A silence or stun can keep you from getting all three of the Q (Broken Wings) charges off. Also, CC lets mages get to safer range where they can harrass you from safe, kiting distances. Mercury Treads should never be replaced on Riven, not even in Dominion.

Youmuu's comes next for the damage, armor pen, and CDR. I always like to pop the active on it whenever I use my ultimate to add to the ultimate damage multiplicitively during auto-attacks between casts. Then Black Cleaver for more damage and speed, then Frozen Mallet for gap closure. With Riven gap closure techniques are crucial. Her 3rd Broken Wings cast and her Ki Burst work very well, but it is always helpful to keep the enemy super slow while you beat down on them. Then Infinity Edge instead of Bloodthirster. This is because Riven is a dangerous champion, and even when played well, she will die in some fights. Infinity Edge has higher base damage and the occasional ciritical never hurt anyone (but the enemy). At this point Riven is fed and probably doing more damage than the enemy can deal with. Phantom Dancer is great for the bonus crit with IE, but moreimportantly the attack speed lets you combo faster. As covered later, Riven auto-attacks between casts and the PD allows her to do so much quicker giving her burst more burstiness.

If the team is short a successful tank, you can build Warmog's Atma's on Riven. It is very respectible, but not quite as preferred.

Riven's Q is a utility. Not damage. It never really does a ton of damage, but it empowers her auto-attack and closes gaps between her and fleeing enemies. Running up to an enemy and quickly using the three charges with no attacks is not nearly enough damage to harrass them effectively. Riven must attack between each Q cast to maximize her potential, ESPECIALLY at level 1. Ki Burst next for teh real damage. It scales with damage very quickly which is why you max that first. Then at level 3 you get the Valor to finish teh combo, allowing Riven to do teh following:

1. Valor into the enemies
2. Q the squishiest one.
3. Attack.
4. Repeat 2-3 twice

Ki Burst when they try to run

This maximizes her damage potential by utilizing her attack buffing passive. When you hit level 6, her ult should be used more often than expected. You want to use it right before you engage to maximize the 20% damage bonus, then finish with the active cone ability after the fight or when the timer is almost up. The ultimate lasts for quite a while, so don't feel the need to run in then activate it. Yu can activate it from the brush, wait a second, then dive in. Also, activate Youmuu's wafterwards to maximaize her damage during encounters. They both have relatively low cooldowns so use them wisely as often as possible.

Rivens overall tankiness and up-in-your-face gameplay makes her a lot of fun to play and very effective in early laning phase. She can snowball feed very quickly after getting her level three combo and can carry games. One thig to thnk about though is the lane partner. Riven does not solo very well when it comes to 1v2s. She can because of her mobility, but she is much more effective in a balanced lane. Some people to look for as your lane teammate are Singed (the fling is AWESOME), Alistar, or even a patient Blitz who grabs AFTER the initiate. Anywhose, have fun playing Riven because when you start to figure her out, she becomes a very amusing champion.