I mained her all season 2, check my build for her below.

INB4 whoa there charles dickens

~boots(turn to ninja tabi or merc treads if your losing lane/ boots of ionia if you arent having issues)/pots,
~rush warmogs, then brutalizer(build this into black cleaver),
~depending who you are top against(ap or ad) build armor/magic resist(like randuins omen or maw of malmortius which end game would both be great to have)
~bloodthirster
~spirit visage(i would build this after black cleaver) or guardian angel(this would be last) work as well.
level 1- Q
level 2- E
level 3- W
Max Q first, then E, then W(as its always a .75sec "stun"), level R when possible

You can use E or Q as an initiator, but when you get to them use your W to stop them. if your ult is up, activate it before going in as it gives you extra damage. Since your abilities "charge" your blade for a little extra damage, I play her as follows:
R,E,W,Q,autoattack,Q,autoattack,Q,autoattack,R again for the finisher(more damage the lower health they are)

My riven guide:
Boots + Pots start
Rush the fuck out of black cleaver
Bloodthirster
Merc Treads
Warmogs
(The game should be over)
GA
Another Bloodthirster

Max Order: Q then E then W
Level up Q first, but try to keep your E one rank below your Q for the CD on it and damage absorption.

Initiate with Q combo, then W-E out

A question for you both: I found that in s3 boots+3 is not viable at all for my main, Rumble. I have movement speed quints, so my base speed is usually above 350, so I usually get 9 pots + wards. It's helped me in a lot of ranked games for early dominance.

Other than that, I usually get brutalizer first, then go BT. You both say it's better to first get more defensive stuff?

WOAH WOAH WOAH, What?

Your runeset on Riven should be AD Quints AD marks MR glyphs and armor seals

Riven is high mobility, MS is not needed on her.

I dont know much about rumble though, just how to mop the floor with him.

I'm usually that 5% that makes people ragequit top. Riven and I do beautiful things to top lane. But the trick to beating rumble with riven is know how/when to poke and get jungle presence.

True. I have played against a riven who knew exactly when to dash away from my flamespitter and popping that ult and dominated the entire lane.

Riving is indeed a nightmare for Rumble's ult, but her shield can't do much against the permaslow + flamethrower.

And that's why you have your Q's, they ignore move speed reduction last i checked.

Yes, but you don't have perma gap closers, and luckily I can still predict where to fire my E at.

Plus, it's horrible to have a stacking slow (theoretically it's a 100% movement reduction) on you.
But that shield, damn that shield

should pretty much always max her e first, q last. Both e and w get lower cooldowns with higher ranks, but this isn't the case for broken wings. The utility it offers early on makes it a lvl 1 skill, but that utility doesn't scale with level.

ummm...isnt that doom bringer from dota 2?

Yeah, it is. Pic was kinda unrelated.

oh. i was wondering that what is a dota picture doing there...

time your Q in between attacks for maximum damage, example being Q - auto - Q - auto - Q auto and finish with what ever combo you wish, ultimate before for even more damage.

um idk how new you are but AA between every Q is huge. a good harrass strat is e in AA w AA Q away. unless you max Q which alot of people do then its e AA Q AA W AA Q AA Q AA. but all her combos are flexible which is why shes fun.

been playing her since release (not so much anymore) whilst this gives you more dps you can spam all your Qs and still get the passive proc afterwards without wasting any through them timing out, if you AA inbetween each skill it takes age to complete a combo and riven is a very bursty character (R E W QQQ R pretty much kills anything with a full stacked BT without auto attacks inbetween)

but then you waste passive stacks with ws and es you might need

the passive has a fair timer on it, sure you waste them but i'd rather kill something quickly than efficiently in a 1v1 situation, especially as her ult is such a short cd even after the nerf

i mean you only get three stacks not the cd on her passive but i also find my self not doing the q aa q aa, its all situational on riven which is why shes so fun, what you max, how you combo, is all different.

with latest nerf i find myself maxing E for survivability in certain matchups

yeah i see people have been doing that, i only do it for poke machines like teemo or jayce or elise. but melee bruisers get the Q