Riven ends up being weak in early-game, she gets stronger with time. Anyhow, this is a jungle guide and I might go for a solo top build on her aswell if this one ends up being good enough! I've choosen the flat ad runes to make her Valor stronger in early game, take less damage of your hp and you won't have to go back that often.

Runes

Flat ad to make Riven's Valor good in early-game. I would perhaps choose to take flat armor pren on the Quintessences -IF- their team ends up having tons of armor, Alistar, Rammus and so on.

Summoner spells

I choose Flash and Smite, SMITE IS ALMOST A NEED FOR A JUNGLER, it will go too slow without it. Flash can be changed into Ghost and Exhaust, I still prefer to use Flash as you can jump over walls and such.

Masteries

12/9/9
Offense: Some ad to your Valor, attackspeed is good for every jungler also you get armor pren!
Defense: Magic resist, health and Summoner's Resolve ! GOLD WHEN YOU USE SMITE! WE'LL BE RICH!
Utility: Movement speed, good for ganks, you'll have red and blue in 20% long!

Items

Build against a team with 50% ad and 50% ap:

1th buy: Cloth Armor, 5 Health Potions in the start.
2th buy: After that you get your Madred's Razors and Boots.
3th buy IF... you've not got any kills: Grab Boots, so it is easier to gank!
3th buy: Wriggle's Lantern.
4th buy: Mercury's Treads.
5th buy: Phage.
6th buy: The Brutalizer also grab the gianst belt if you've enough!
7th buy: Frozen Mallet.
8th buy: Warmog's Armor.
9th buy: Atma's Impaler.
10th buy: I am getting tired of this... anyway let's continue with Youmuu's Ghostblade also you sell Wriggle's Lantern now for the last item.
11th buy if you took Berserker's Greaves then go for Bloodthirster, otherwise go for Banshee's Veil. This build will give you more armor than magic resist but you can always change some runes if you want to get some more magic resist.

Against heavy AP

1th buy: Cloth Armor and 5 Health Potions.
2th buy: Madred's Razors and Boots.
3th buy: Wriggle's Lantern.
4th buy: Mercury's Treads or Berserker's Greaves if they don't have any slows, stuns and such.
5th buy: Phage.
6th buy: Hexdrinker.
7th buy: Frozen Mallet.
8th buy: Banshee's Veil.
9th buy: Warmog's Armor.
10th buy: Selling Wriggle's Lantern for Bloodthirster.

Against heavy AD.

1th buy: Cloth Armor, 5 Health Potions.
2th buy: Madred's Razors and Boots.
3th buy: Wriggle's Lantern.
4th buy: Ninja Tabi or Berserker's Greaves... nothing wrong with attackspeed! I choose to use that kind of boots if you don't have to dodge anything.
5th buy: Phage
6th buy: Frozen Mallet
7th buy: Warmog's Armor
8th buy: Atma's Impaler
9th buy: Sunfire Aegis
10th buy: sell Wriggle's Lantern to get your own personal Bloodthirster! That you can stack...! Don't die as you lose your stacks...!

Play Video /league-of-legends/item/madreds-razors-78

Where to start?

Blue buff! CD's and you're lvl 2 afterwards... YAY! Anyway, make sure that you spec Broken Wings first and get a pull so you don't fail.
When you're lvl two go for Valor if you're not going to gank in lvl 2, then you should more likely go for Ki Burst and then later on in lvl 3 go for Valor.
If you continue to jungle then go for wraiths and then the two golems.
After that you're lvl 3, go for Ki Burst and STUN THE RED BUFF! If you've not speced Ki Burstfor ganking in lvl 2 that is.
Now you're lvl 4! Go for Valor After that you should probably gank if you've not done that so far.

I wish you good luck! it took me some time to create this guide, I hope it helped you alot over all, this build works on lane aswell but I know starting with a dorian's blade would do alot better than a Cloth Armor and 5 Health Potions. Also the masteries should be changed some.