PROS

+NO MANA
+LOW COOLDOWN REDUCTIONS: MEANING YOU CAN SPAM YOUR ABILITY'S(I dont recommend spamming for no reason)
+OVER POWER EARLY GAME
+THERE IS NO SUCH THING AS COUNTER
+TURRET DIVE...early with jungler(level 6 to do it by yourself recommend)
+EXCELLENT SPLIT PUSH
+ CAN 2 v 1
+SNOW BALL POTENTIAL

CON

-DENY CS
-AP CAN DAMAGE YOU PRETTY BADLY EARLY(rush HexDrinker)
-Lose trades if you cant land W
-Range champs will destroy you early

AGAINST CHAMPS LIKE DARIUS, IRELIA, SWAIN,GAREN,PATHEON, and champs that you know will give you a hard time, I recommended double jungle. Rivens Q combo will delete the monsters health near zero and will give you the upper hand to help clear jungles easier. If you dont know double jungle, I highly recommend watching this video Play Video

AS YOU SEE BOX BOX IS A VERY SKILLED AT ANIMATION CANCEL. (AA-Q-CLICK SOMEWHERE-AA) and repeat 3 times. IF YOU THINK THIS IS TOO HARD THEN PRACTICE THIS (AA-Q-AA-Q-AA-Q-AA)
My favorite move against a lee or a engaging champion is wait for them to almost hit then press W, I promise you it will stop there movement and E out or Q combo then E out. Play Video

Getting ganked is going to happen to you, you must be prepared at all cost, with season 6 you dont have to waste on buying wards but buying pink wards is necessary, and I will tell you why.

During your time farming with Riven and the other champion is playing safe, you dont get no kills right? What a sad day, O wait, there is another champion that spends time in his jungle. Ward his red buff with stealth if you know he will go to his jungle. Ward with pink if he is going to take his time somewhere else.HE GOES IN TO TAKE BUFF U END HIM.

IF HE IS NOT THERE, CLEAR HIS JUNGLE WHEN YOUR OPPONENET LEAVES LANE SO YOU CAN OUT LEAVE HIM. ALWAYS GET THE RIFT SCUTTER. use your W to lower its Armor and kill it with Q combo. MINIONS AND JUNGLE BUFF ARE VERY GOOD WITH THIS masteries CAUSE IT LAST LONG.

Try to snowball with this masteries, get jungle help if you have to. You will be unstoppable.

Riven is very simple yet complex

you want to do as much damage as u want and leave without a scratch, close combat with a w and Q combo and use E to exit out of the combat.
Ranges: Plz use ur E to get close, also use the bushes to get close but never use ur Q to close the gap(it might be the end for u) You will trade with less health and less damage.

WHEN YOU WANT TO LANE AS A RIVEN, it will take patience, I like to harass at level 3, but in certain situations like a Garen harass at level 2 when exp is near level 3.

You want to push the minion waves quick and make sure to not waste a single creep.
Push your lane hard so you can level up quick and go back when your at least 20 minions above. Or if you have enough coins to buy your first items.

WARD your area. AND IF YOU WANT TO BE A RIVEN GOD, call your jungler for help to get that early snow ball potential.

WARNING!!!!!!! IF your winning your lane and a the oppenent all of a sudden wants to fight like he is Mohammed Ali, RUN TO YOUR TURRET, its most likely a gank

YOU DONT WANT THE GAME TO LAST TOO LONG, as RIVEN you might get out beat by Irelia or a team that has better synergy. If you are winning your lane, push to the tower, destroy your tower and help your team win their lanes. After that you can switch back to your lane and push hard as your team pushes hard because well your a good split pusher.