After a few games I found what works best for Riven is to build her as a pure AD DD (champs like Talon), this works better than Tanky AD (champs like irelia or renekton) or AD Crit/Atkspd (champs like shaco or tryn) IMO

Pros:

AD Nuke, can kill squishies easily by spamming
AOE Skills
Riven is a very mobile champion
Hit and Run gameplay
You can deal damage endlessly w/o the need for mana

Cons:

Not as effective vs Tanks
Mid - late game you will rely on E often for survival
BF Swords are a pain in the *** to get

Skill Sequence:
Attack: R > E > Q > Q > Q > W > R
Retreat: E > Q > Q > Q

you can also use your skills to move around the map

and if you can try to steal the enemy's blue buff, the Cooldown reduction helps greatly

gl hf