After playing a lot of riven, i decided to share my build
This build doesnt make you invincible or whatever,, you will be able to survive for a long time but like i said it doesnt make you invincible.
Let's get started then!!

Pros:
Really mobile for a solo top
Hard to gank
OMG NO MANA NOR ENERGY
Has this lovely shield to protect herself
Great 1v1er
did i mention yet, no mana no energy?

Cons:
She is quite squishy
You need to have some sort of skill to play her
Her positioning is crucial

9x Greater Mark of Desolation Nothing else to pick than this really, maybe Greater Mark of Strenght but these arp runes just help you so much to shred their armor early on.

9x Greater Seal of Armor Hey i am solo top, can i have some armor please? Here we go flat armor runes

9x Greater Glyph of Scaling Cooldown Reduction She doesnt have mana, no energy or w/e so her abilities are important!! You can always swap out to 9x Greater Glyph of Scaling Magic Resist

Start off with Doran's Blade, if you are in an easy 1v1 lane, in a hard one you should pick up Boots + 3x Health Potion although you can run with Doran's Blade
THen you will want another Doran's Blade. As boots you will want to go for Ionian Boots of Lucidity. After that a Phage and a The Brutalizer.

So your core build will look like

2x Doran's Blade Ionian Boots of Lucidity Trinity Force Youmuu's Ghostblade

From here on it is just personal choice and how the game goes...

If they have heavy cc go pick up Mercury Treads, if they have heavy ad go pick up Ninja Tabi

So now we have our 3 main items, we need to go and look for 3 other ones
normally i run with atmogs, which in my eyes is the best choice and then finish off with Bloodthirster

Other items like Force of Nature Randuin's Omen any defensive items you want,, but i would really suggest going with Bloodthirster

It is really personal preference and how the game goes in the end,, need more MR pick up banshee's or FoN,, need more armor pick up Randuin's or Thornmail,, need more hp go run with atmogs, i almost forgot Guardian Angel this item makes me rage on the right champions,, although i don't really like it with riven too much haven't tested it out as much either, but if some1 does please let me know how it went.

The must have summoner spell is Flash
Then your 2nd summoner spell is your own choice,, you wanna go for a FB go with Ignite otherwise pick up Exhaust
nothing more to be said really only these 3 or gtfo,, you can also pick up Teleport but i just dont like it as much as those other 2

I hope you enjoyed this guide about riven, it is my first guide after all so go easy on me. I can always go and make this an in depth guide, if you guys want it ofc. Anyhow gl&hf with playing riven, and remember to play agressive on riven.