Ok so this is my second build that i have made. I will be explaining her Runes, her Masteries, her items, her skill sequence, her summoner spells, some pros and cons and how to farm with her.

Pros

Great damage mid and late game
Easy farming (not as good as the best but getting at least 80 minion kills)
Lots of kills
Good escape capabilities
A stun!

Cons

Easy to die and low damage beginning game
Against stealth like eve dies a lot
Bad solo capabilities

ok so i get flat crit chance marks because the more you can crit early game the less you'll die i got flat armour per lvl seals to help survivablity and flat magic resist per lvl glyph to help against mean ap guys finally i got flat crit damage to help that massive damage output.

ok so i got the deadliness for crit the exhaust so i can get more in offense or you could use exhaust as a summoner spell sorcery really helps with the cooldowns and some added attack speed can't hurt. i got some magic resist and armour for defense Masteries some survivability there and good hands as well as perseverance for the health regen and to keep alive longer. the haste really helps getting away and you can always use some more experience to lvl faster and the gold is helpful sometimes.

ok so first i get the Dorans blade purely for the damage and life steal but the health helps as well. next i get mercs treads as it helps with magic resist and you can get rid of that nasty cc faster. i then get zeal which leads to phantom dancer which gives me a fair amount of attack speed and crit as well as some nice movement sped to run away or kill a runner. the infinity edge helps her abilities damage out put as well as giving even more crit. blood thirster again helps damage and gives heaps of lifesteal so you can kill to gain health! finally the black cleaver helps with the armour pen and damage so by the end you crit heaps and do a **** load of damage

ok i get broken wings to help the farming and cc a bit then the ki strike for the stun and finally the valor for running or catching up to an enemy.

so heres my combo for killing someone i charge in with my E i use my ulti to get extra damage then i keep up if their running away or even if they are just standing there with my Q i then use my W to stun them and then use my ulti again to kill them quickly or to kill a wave of minions.

ok so farming is pretty easy with Riven you just either last hit minions or use your Q or your W and kill them with your auto attack if you used your ulti against a champ but he/she got away then use your ulti again on a wave of minions to kil them for some easy farming.

ok so for summoner spells i get flash and ghost
i get flash to catch up to a running away champ or to run away
and ghost for running away or getting from bot to top or top to bot quickly

other good spells would be ignite, exhaust or teleport

any others are really just useless.

Early game-try to stay near your laning buddy and just farm a lot but if a good setup for a kill is there chase them and kill them (but don't over extend or chase too much)

Mid game- ok so by now you should at least have you phantom dancer you can start to kill lots of champs as well as maybe take a few turrets but again don't over extend or chase them to a turret you WILL die. also watch for ganks

Late game- now you should have an infinity edge or if your doing really well your blood thirster try going for the guys that straggle off or anyone that comes near your team. also helping kill the enemy nuke is helpful.

ok so last chapter i hope that this build was at least helpful to some of you and that any feed back is really welcome and if you wanna add me on league i'm minkk1996 oh and don't forget she has a stun!