Let me just say this is my first build. When Riven was first released, I knew that I had found my favorite champion. Although many people say she is UP, I have to disagree with them. She may not be the easiest champion to play, but a champion like Riven takes dedication, experimentation, and overall a lot of practice. With this build, you should be able to give a good amount of damage and take a good amount of it also, given you know when to pop in and out to attack your enemies. As I've said before, Riven takes a lot of practice to learn. This build is how I use Riven and is to merely show others who might be interested in using her in a similar fashion.

Pros
Good damage output
Amazing mobility (really helps in chasing or getting away
Very good at ambushing and surprise attacks
Good in a team fight (Her knock up and brief stun can stop channeled abilities)
She carries a giant bottle opener

Cons
Shes very squishy early game
Lack of good CC (Her only cc is her .5 second stun)
CC will rip her to shred

I ALWAYS take exhaust when playing as Riven. When I first started playing League of Legends, I had never realized what a great spell it was. My first game as Riven I went Exhaust and saw how much it had helped Riven. I mainly use it when starting a fight. When an opponent initiates a fight I have noticed they will not back off when you exhaust them. With Cripple, Exhaust becomes a very great debuff on your opponent, you should be able to tear them to ribbons with Riven.

As for Ignite, I take it to stop things such as self healing. It also has a little annoying dot that has killed me so many times its not funny. Its also very good in neutralizing a support character while you chop their DPS champs. All in all, Ignite is a very good spell that can become a kill or turn a fight in your favor.

Feel free to change out summoner spells to your liking, I am simply stating why I take these spells. As long as you know how to use your summoner spells with Riven, you should be A-OK.

With my masteries, I really try to build to the offensive side of Riven by building on trying to rip an opponent down as quick as possible, Especially with Havoc. Riven starts out with a good amount of attack damage, but with the 4% increase in damage she becomes even deadlier.

Although I build towards a more offensive Riven, she does need defense which is why I take Hardiness and Resistance. It helps with those early game fights that can turn the tide of the match.

I take boots of speed and 3 health pots first. It helps you stay in a lane much longer so you can afford your Mercury Threads and the pieces for your Thornmail or Silver Sash (really depends on who your laning against). Once you have your Thornmail/Silver Sash, start getting The Brutilizer because your opponent will start stacking armor undoubtedly. Turn it into a ghost blade as quick as possible and then start trying to get your Bloodthirster. Once that is done, start picking up health items such as Frozen Mallet or Warmogs Armor.

Really, it depends on what your up against. If your going up against an AP heavy team, you should stack magic resist items such as Silver Sash (which helps with one of Riven's Achilles' heels). Stacking health may also be a good idea for Riven since she can be very squishy.

One thing that is Core for her is The Bloodthirster, and Youmuus' Ghost Blade. The armor pen from the Ghost Blade and the damage from the Bloodthirster makes Riven do insane amount of damage against AP carries and unarmored opponents.

I usually start out with Broken Wings because of the mobility it give Riven. Sure, it doesn't give you the temporary shield that Valor gives you, but it helps you in harassing your opponent a lot and being able to scare them off. I have noticed that the more you harass your opponent, the more scared of you they become. Once you become in control of their lane, they'll begin to panic and ultimately you'll have them on their knees.

My first point goes into Broken Wings, second into Valor, and third into Ki Burst. Ki burst is the skill you want to finish last. It's a great skill and all, but the only thing I really use it for, is ambushing and stunning my enemy to have that critical chance to either let my lane partner take care of them, or begin to chop away at them.

I rush Broken Wings because of it's damage. It is also her main attack ability other then her passive. Valor is the second skill I finish mostly because the shield she gets scales with AD meaning the more AD you have, the more damage you can take...insane isn't it?

Riven's bread and butter is her passive ability, Runic Blade. After every ability, Riven can do extra damage with her next auto attack. This means to really get the benefit of your passive, you must space out your abilities. Timing is key when playing Riven.

The main combo I use is:
Valor, <AA>, Ki Burst, <AA>, Broken Wings, <AA>, Broken Wings <AA>, Broken Wings <AA>.

It might not always end with a kill but it'll sure as hell scare your opponent.

If your chasing a champion it may be best to use this combo:
Broken Wings X3, <AA>, Ki Burst (once you've caught them, you may need Flash or Valor), <AA>x3, Valor <AA>

Good Laning Partners

Brand (or any burst AP champion) - His burst damage will provoke your opponent into stacking magic resist. When that happens, you'll be able to cut your opponent to pieces because they will fear Brand's hard-hitting spells.

Kassadin - His Force Pulse charges with your abilities and you WILL be using your abilities a lot. This benefits you and your partner because he can slow them while your hacking at their back with your giant bottle opener.

Xin Zhao - Xin Zhao's knock up and good damage along side your tiny stun, knock up, and your awesome damage make one hell of a beat down when fighting AP carries or any kind of squishy champion.

AP Tank (Ammamu or Cho'Gath) - Cho' Gath's knock up and silence gives you that critical edge in a fight to be able to take out your opponent. Ammamu's double stun can also really help in Riven's favor.

Ranged AD (Ashe or Vayne) - Vayne's Condemn can really help given that your partner knows how to use her. She can shoot an enemy your way to slice up like butter, or pin them to the wall. Doubled with your cripple and the massive damage both champs do should equal a kill. Ashe's ability to slow will help you catch opponents before they get away. All in all, they shoot, you chop, everyone wins.

Worst Enemies

Tryndamere - The biggest enemy of Riven. Riven's biggest asset is her awesome attack damage, Tryn's biggest asset is his MASSIVE damage. He starts out with more damage then Riven, he attacks faster then Riven, and he is super hard to kill because of his Undying Rage. If your laning against a Tryndamere, make sure you have a partner with a good amount of CC.

Warwick - I can't tell you how many times Warwick has almost killed me. Its not his attack damage that kills you, but his ability to outlast you in a fight will make Riven seem pretty useless. When laning against a Warwick, its probably best to have an AP nuker with you.

Shaco - You can fight a Shaco all game and not even know where he is most of the time. You won't really be laning against him, you'll be more along the lines waiting for him to pop out of his hiding places. If you've got a Shaco on the opposite team, be ready for one hell of a fight.

So all in all, Riven is a meat cleaver with legs and white hair. Don't neglect your defenses though because a dead Riven is a useless Riven. Take advantage of those critical seconds you have with Riven's stun and Valor shield.

I thank you all for reading my guide and taking the time to look at it. Most of the things I wrote on here is from experience, If I missed something, feel free to let me know about it. I take constructive criticism well and am willing to change my build if I feel it necessary.

Thanks again for reading my build and please don't thumb down just because of how it looks, try it out first please.