First off, my builds are short and to the point. I dont explain much but i do try. My name is Sylar and my champion is Riven. Since she was released i have seen the smallest amount of players using her, as a new champ thats very surprising. When i first used her i was amazed by her skills. They were the most diverse and flexible skills i had ever seen. As always, when i first started using her i looked up a MobaFIre build to base my build on but when i looked at all of the builds i was pretty disappointed. So here i am, presenting my build. Enjoy.

P.S If you don't understand the title, quit now :)
P.P.S Im rude and so please understand when i say "figure it out" because i say that a lot.

Q and W. Wow. The best farming skills ever. Use W to lower the creeps and Q to finish them off, no mana, no loss.

Yes i am starting with Runes. Why? Because you dont need them so it will be my smallest 'main' chapter. I have all of the runes i put for this build but when i play Riven i take them off. *But Sylar, why would you do that?* Try her without the runes, you'll understand. Once you get a hold of how to play her, put em on and you'll be indestructible.

I dont really get why people explain Masteries on MB, so i wont. Read the little thumbnails when hovering over the mastery icons and figure it out.

If you read the AD ratios for her skills you'll understand why i chose the items i chose. They help you chase, kill and run.

Q is the best hands down. W stuns, and E saves you. Her ult should be used as a finishing move, no i dont mean activate it at the last second, activate it when you start a fight. You then have 15, yes 15! seconds to user the second part of her ult. When they're about half use the second part and walah!

Flash - Just in case,i have escaped from 3v1 ganks before without flash and just using what i told you before but there are those times...

Exhaust - For those OP DPS killers, and to escape.

Riven is amazing, dont take that lightly. Practice in Custom Games with the teams being the following:

[You] vs [Shen]
[Soraka] vs [Malphite]
[EMPTY] vs [Nasus]
[EMPTY] vs [Soraka]
[EMPTY] vs [Yi]

Why? Because it actually gets pretty tough to win, Shen will save whoever you're killing. Nasus and Malph get pretty tanky, Soraka will heal whoever you're killing and Yi runs ( =] )

I hope you learn from this build, Enjoy.

P.S I actually use pretty much the same exact build for Lee Sin so try this build out with him too, it will work wonders.