so I like playing riven and I'm pretty decent at playing her but I don't play her much so I don't really know the right items/skill order and what not for 3s. Any tips would be appreciated. I normally jungle with her if that matters.

anyone?

usually how i do it is r>q>e>w vs low mobility comp, r>w>e>q vs high mobility comp. if you can't land q on anyone, it's better to max w

a good build is to start boots + dorans blade (or double dorans blade) then pillager. rest of the items are situational. she's a very hard champ to build imo, so it's up to you to build whatever you feel most comfortable with

I play a LOT of Riven. I main her in the jungle in ranked games. She is one of the most versatile champions in threes and has a lot of utility.

I agree with Boo as far as R>Q> but your e and w can be upgraded depending on the situation. If you are finding the team is bursting you down or that you are behind, then it is a great idea to upgrade your shield first. If you find you need more damage or you are just dominating and don't really need your shield, upgrade your stun for extra damage.

As far as build, as I said I jungle her so I always build a lantern first. If you do not jungle her then you don't need one. It is useful if you are against a champ that cloaks (Like wukong). Your core item should be a Pillager. It gives you everything you need, spell vamp (you gain life from your splashing q and w, health (I build her as a bruiser), and damage. After that it is entirely dependent on the team and if you are winning or losing.

When behind consider the damage out put of the opposing team. If they are mainly AP, then grab a Hex Drinker, build it into a Maw and pick up Merc Treads. If they are doing mostly AD you have two options. A. Build a frozen mallet if you are not too far behind and follow it up with an Atmas. B. Build a Wardens Mail (probably the best armor item in TT) and upgrade into a Randiuns later on. Either way you should pick up Ninja Tabi unless they have stupid amounts of CC, then pick up Merc treads anyway.

If you are ahead you can go straight into a Frozen Mallet followed up with a Sanguine Blade.

A few other situations you should consider:

If you are being tank rolled and they are stacking armor then try building Pillager, Brutalizer and follow up with a last whisper. You will shred straight through their armor.

If you are against a Mundo or a Voli then rush a hatchet. It pays off in spades if you can grab it around the time Mundo hits 6. Bait him into a fight and watch as his ult does diddly squat.

The last item I pick up every once in a while is Sunfire. It is awesome on Riven, I just find I don't have room for it. It's great if you don't jungle and have the free slot I fill with a lantern.

Anyway, I hope that helped

everything he said plus:
runes: armor pen marks, armor seals, i use flat CDR gliphs but flat or per lvl MR good too, and i use move speed but ad quints good too.
masteries: 21/9/0 i put two in the cdr, go standard ad for the rest, get armor one in mr then the hp ones in defense
items expanded: after pillager get blade of ruined king if way ahead, always get at some point though, otherwise get phage then either maw if you need MR or a chain vest if need armor then the blade of ruined king. you turn the vest into a randuins or a atamas depending on how much you need later. siguine blade good, but always botrk first. and get a last whipser if they stack armor. common builds look like: boots, piliger, frozemallet, blade of ruined king, maw, singuine blade or randuins or atamas for last spot

I'd say that flat MR is better in TT. Games often do not go all the way to lvl 18 and the early game MR helps a lot.

BotRK is not as awesome on Riven as it is on other champs. She does not auto attack as much in a team fight relying more on burst from her abilities and damage from her passive.

few problems with your building:
-Frozen Mallet is situational. Once you get on someone you stick regardless of the slowing effect imo, unless the champs you're up against have ridiculous run speed. I prefer Aegis of the Legion, particularly in 3s where you don't get to very late game often.
-Pillager, Brutalizer and Last Whisper in the same build set: No. Stop that. I actually would only build Last Whisper if I didn't have any flat armor reduction, since they reduce each other. When S3 Black Cleaver comes out, I'd build that every time, though.
-Sunfire Cape. What is this? It doesn't provide anything Riven needs. Randuin's Omen at least gives you sticking power and a minute amount of CDR.

My favorite 3s Riven build:
Tabi/Treads, Aegis, LVDP, Sanguine Blade, BotRK (will be amazing in S3, but for now, a situational item for getting onto people) or Randuin's Omen, and Maw of Malmortius.
Once S3 hits, Black Cleaver is a must.

Edit: Also, in lane, I like to max W first, as it lets you harass without penalty constantly and gives you immense sticking power. I max E next, then Q; I mostly use Q for the passive procs. This is why I build more AD than defensive.