I'm not into writing guides, nor by any means do I have any business doing so. I'm not going to write out reasons for every item. There will be a ton of hate because there's "THIS ITEM and THAT ITEM.""THEY WORK BETTER ON QUINN." Then make a guide of your own. There's a total disregard for 3v3 guides with tons of champs and I'm going to at least give people some idea of what they should be using as far as runes and masteries. Again, I don't care about your build. If your build is so great post it up and I'll be glad to give it a try. This is what has worked for me every game so far and in my opinion through my 50+ games with her this is the best build. I may or may not add on to this in the future. Give it a try worst you can do is get wrecked.

Starts will all vary on who you're facing. Facing a AD heavy team ? Buy a cloth armor and boots. Facing extremely AD heavy team ? Buy a Chain Vest. These factors typically determine what you're first items will be. I will almost always start double LS because your Q is a poke. This will keep your laner at bay. I.e. you shouldn't need the armor if you're not taking tons of hits to the face.

Berserker's Greaves - Only boots I will ever use on Quinn. Mind you late game if you've snowballed heavy: You don't need boots. Fly everywhere. No one will catch you while flying. Wanna fly faster ? Get some Boots of Swiftness.

Death's Dance - All around solid item. +75 AD while granting CDR and a passive on hit heal. The bleed works with and against you. Yes, I have let that bleed kill me before trying to gank. Don't engage unless you are certain you can take the 5 second bleed effect.

Lord Dominik's Regards - Lets face it. You're squishy. Most enemies will have more HP than you. Giant Slayer Passive helps with that. Giving you a 1.5% bonus damage boost per 50 HP. There is a cap of 500. Most likely your enemies will cap that for you by building ton's of HP or Armor. Why does the armor not matter as much ? This items other Passive ignores 45% of their bonus armor. Added with this items +50 AD it's just a all round good choice.

Banner of Command - Having a hard time staying in battle ? This item gives you boosts in the Magic Resist, Armor, Mana AND CDR. It's active grants a minion in lane a boost in power and makes it immune to magical damage. I hardly use it. But could be handy. You're going to want more mana because your R uses 100 and with a typical cooldown of 3 seconds you're going to be popping that all day, son.

That's all I'm doing for tonight.

Harrier is a life saver. Learn to use it effectively. When you're getting more AD you'll be able to one shot Q groups of minions no problem. Quinns mobility is Grade A on ANY map. This mean you can stay in the team fight longer while not worrying about the minions about to crush your tower.

Flash - First spell should always be flash. You have a TON of burst damage but you most likely will be a glass cannon for the first part of the game. You have a great escape tool (Vault) but remember champs like Vi. If you vault off her if she hasn't burnt her gap closer she WILL catch you. Flash away. Over walls. Juke flash. Whatever. Stay alive.

Exhaust -Second spell should be exhaust. Say in the Vi situation you need to vault away from that B. Exhaust her first. Then Vault. Exhaust on Quinn should be used as a escaping tool firstly, and a killing tool secondly.

Ignite - Lately I've noticed I should have been taking Ignite because enemy champions have been escaping with little life left. One pop of Ignite would have netted me at least 3 more kills a game. But you have to figure in how many times you would have died had you not had exhaust to save you. Because let's face it, 3v3 Flex teammates aren't the brightest bunch and won't typically do what needs to be done to either save you or neutralize the threat to you.

Heal - If you think you need more sustain then take heal. It really is a great skill. You can stay in lane longer. AND heal up teammates. Especially your jungle before a gank. When you get better with Quinn you'll find yourself taking this a bit more because you won't need the exhaust. When you're damn good with her you will take exhaust though. You're going to be jumping in and out of team fights so fast that you shouldn't be taking a ton of damage and you'll be using that exhaust for it's secondary use ... killing.