Won't bore you with a wall of text. But this build is ment to be a poker. With this build i constantly am able to be on someone while doing a decent amount of damage while stun locking their abilities and absorbing their hits. Its a great build when chasing an enemies past their turret or holding your own till reinforcements come.

Pros:
High HP
High HP Regen
High DEF
High RES

Cons:
Low Tenacity
Avg ATP
Avg Armor Pen

First things first, the abilities that Riven has are very very important. How and when you use them determine how well you can play as her. CD reduction is there so that you can use your abilities more often. This is good because she has three damage abilities. One acts as a knock back, one as a temp stun, and last is for increased damage and ranged attack. The last is the mitigation. At the end they become quite spammable.

Runic Blade
The reduced CDs also have a major benefit of activating her passive. The more times you use your ability the more passive attack power she gets. This ability has to blend into your play style if you want greater damage output.

Broken Wings
This ability can be used three times in a row if you desire and at the third attack yields a knock back. Every time you use one of this ability you get a stack of Runic Blade. Ideally you want to intermix this move with a normal attack. This applies your Runic Blade and deals extra damage. The benefit of this move is that it gives you a slight move increase. This can help you keep up with running enemies while dealing your normal attacks.

However has a slightly longer CD which does not decrease with your skill lvl. Which is why I tend to upgrade it last but invest in it first.

Ki Burst
This is the move that I focus on first. This deals AOE damage in a very short range but also stuns as well. The stun is not ment to hold them forever but just to interrupt movement and casting. I use it in conjunction with Broken Wings. Cast BW once and then KB. This stuns them for a single hit of RB. Then BW, normal atk, and BW again. Inter mixing your abilities allow you to keep up with your target and deal massive damage to them. This ability also has a CD which decreases with skill Lvl.

Negative part is the range. Very easy to miss if not timed right.

Valor
This is another great ability Riven has. She launches herself forward and applies a shield. This can be used to absorb a players counter attack and give you dominance in a fight. Cast it often and it keeps you in range of your target as well. It can be used to dodge skill shots as well. Even if you don't move to far out of the way you still get your shield up.

Blade of the Exile
Reforge your blade and your epicness starts. Your atk range increases, damage output increases, and you also get a ranged cone shot which deals more damage based on the targets health. The CD also goes down as you lvl this skill. I have gotten my CD down to ~30s with this ability which is OP.

How you play Riven will depend on your reflexes, patience and knowledge of your opponents. In order to deal greater damage output's you will need to have patience and use your abilities at the right times. I'll explain some techniques I have picked up while playing Riven.

1: The Survivalist
For this its basically monitoring the times you use your Broken Wings, Valor and Ki Burst. These can be used to keep up with running enemies, to run away from aoes and groups, and can interrupt casts like those from Miss Fortunes Bullet Time or NuNu's finisher. Use these abilities effectively and you can keep your self out of their range, save your life and do some damage. With the HP Regen this build has you will have your health all back and be able to continue to bother them.

2: The pest
Instead of blowing Broken Wings all at once and trying to deal great amounts of damage in a second, you should space it out. Try to time it so that you keep up with a fleeing opponent so that you get this type of effect.

Broken Wings-Normal Hit(applies Runic Blade)- Broken Wings-Normal Hit( Runic Blade) and so on.

True if you do it all at once and you get the stack, however the stack only goes to three, and if you use your other abilities at full stacks your wasting some potential, plus you may end up lagging behind the target if they run away and you have no Broken Wings.

3. COMING SOON-just gotta refine a few more points then ill post it.

Greater Mark of Desolation
This is for true damage, as the game progresses armor ratings of all players will start to go up, and you will need to get through that to have a chance.

Greater Seal of Armor Greater Glyph of Magic Resist
This is for greater armor and resist, should give you an advantage against any players you are playing against in your lane by reducing the damage they deal to you.

Greater Quintessence of Cooldown Reduction
Lastly this is to help your overall skills. Riven is not bound by Mana or Skill power or rage or anything like that. All there is are Cool Downs. Logic stats that the shorter the CDs are the more mitigation and damage you can deal.

OPTIONAL
Greater Quintessence of Attack Damage
This is another option if you would like to use. Greater Attack is better at the start of the game, however it tends to become worse over time. With the CD reduction it will be constant throughout the game.

Doran's Shield-Good starting item, increases armor and Regen so that you can take some hits and regen hp faster.
Vampiric Scepter-will help with a future item and is very helpful for regen
Boots-boots to help you move faster
Wriggle's Lantern-Armor,LS,Attack what doesn't it have for a melee fighter
The Brutalizer-CD reduction, Armor pen and Attack very useful
Phage-Helps keep your enemies near you
Ionian Boots of Lucidity-Helps with your CDs and speed
Frozen Mallet-Lemme Lemme Upgrade
Atma's Impaler-Crit, armor and ATP based on health, since this build is HIGH hp VERY god
Warmog's Armor-Helps you get high HP and regen
Youmuu's Ghostblade-Another upgrade with VERY useful active
Force of Nature or Randuin's Omen- It is up to you now where you go with this, you can get rid of your boots if you like but it depends on what situation. Force of nature will boost your HP regen tremendously to the point where you are getting like 100+ Hp/5s, plus helps build up your Magic resist which is lacking at this point. However Randuin's omen gives armor, some hp, some regen, but some very useful things that counter melee targets. Choose one to your style.

Depending on your play style you will have your preferences. I chose my Masteries such that it upgrades my two most common.

Flash
Best ability for Riven, once in a while you will notice that your character will get stunned and then ganged up on. This ability is an escape and a chase ability that you can use to avoid or take down an opponent.

Exhaust
Slow and armor reduction lets you take down an opponent faster and keep them from running very self explanatory.

OPTIONAL

Heal
This can be used to help you keep yourself up, can be used in dire situations or just reassurance you wont die. With the HP regen and LS in build you most likly wont need this skill.

Teleport
Skill is good for getting around field fast and also allows you to retreat and get back in a matter of seconds.

This is a quick guide to how I play Riven. Originally built off other guides i tweeked it to my own and hope you enjoy how it plays.