Riven is new so I expect to change this guide the more I see her played and as I play her but so far this is what I expect she will do well with. When you are playing her always make sure to do a basic attack in between your Broken Wings to get the full effect of her passive.

I went with Greater Mark of Desolation because of course we are a melee DPS, and Armor Pen is the way to go if you want to hack people's heads off. Then seeing as how Riven doesn't utilize mana I decided to make her a more formidable 1v1 champion by giving her armor, magic resistance, and health with Greater Seal of Armor, Greater Glyph of Scaling Magic Resist, and Greater Quintessence of Health.

For masteries I went with a 21/6/3 build. Riven needs to of course be focused mainly on damage, then I got some defensive abilities since she doesn't really need mana regen.

Doran's Blade to start out just to give us a little survivability and Attack Damage, after that Bezerker's Greaves don't worry we're going to get our tenacity next from Cloak and Dagger.

Now start saving up and farming for that Infinity Edge which is really going to start making you a formidable opponent on the battlefield.

After that comes Frozen Mallet to give us more survivability.

Then Wit's End for some more magic resist and attack speed, not to mention the magic damage since Riven only does physical.

Afterwards you can grab Black Cleaver or Last Whisper if they are stacking armor against you.

I put my first level into Ki Burst because of course its a stun and it could potentially get us that first blood with our laning partner. Afterwards Broken Wings is going to be our bread and butter so we need to get that maxed out first while leveling Ki Burst as its going to synergize well with Broken Wings.

Valor Gives us a little more survivability but it isn't as important as the other three so it kind of slips by the wayside while we are leveling.

I got Flash for that escape or chase whichever you prefer to use it for. Then I have Exhaust to slow down that fleeing target while you go in for the kill.

I hope this build does well for you and you rapeface with it. Remember to do an auto attack in between your Broken Wings.