Wanna play Riven top?
Don't freaking max your Q first.
Q>W>E>W>E>R, and then max W, E, Q. Q first Riven is for midven.
Now, Q, AA, Q, AA, W, AA, Q, AA, E combo is amazing for harrass if you're not afraid of taking a hit.
E, W, AA, 3Q getaway is good for going in, bursting a bit of damage, and getting out without taking much damage.
There are plenty of more combos to max out her passive use and to deal/mitigate damage, but I use those the most.
Don't go Black Cleaver first. Boots+3/longsword+2, Vamp Scepter, Brutalizer, Situational boots (Tabi/Treads), Bloodthirster, Last Whisper, Warmogs, Black Cleaver, Guardians Angel.
That's my usual build over the course of a game.
Runes: Typical top runes, AD/pen marks, AD quints, Armor/MR seals/glyphs.