This guide is a clean (Non-colorful) guide for if you want to try Quinn out or just want another opinion.

This is also a Work in Progress. Some information may not be added yet, or may be edited later.

I'll explain:
Runes: Which ones to get, and why I recommend them over others.
Masteries: Why I chose them, and why I recommend them over others.
Summoner Spells: Which to use and why.
Skill Sequence: Why I chose which skills to get and max first over others.
and
Item Build: What to get, when to get them, why to get them, and explain why I recommend them.

I won't just give you a list of items, say these are the core items, and let out figure out what to do on your own.
Nor will I lay out a dozen alternatives to satisfy every player's opinion (its a guide, not definite path or way of playing)
There are no fancy word wraps, extra images, videos, bragging about how many victories I've gotten, who your friends should play to support you, or who to avoid.

You most likely can't choose your enemies, and if your playing with randoms you usually can't choose your laning partner's champion.

I only hope you'll learn something from this guide and possibly take something away to add to your own build and your own play-style.

9x Greater Mark of Armor Penetration
9x Greater Seal of Armor
9x Greater Glyph of Magic Resist
3x Greater Quintessence of Health

I take flat runes because early to early-mid game is essential, and most runes (not all) matter less and less as you get to late game.

Greater Mark of Armor Penetration- Take these because they don't decrease in usefulness as the game progresses as much as Attack Damage Marks do.

Greater Seal of Armor- AD Carries are usually "Squishier" than other roles, so the extra armor early game can help you get an edge over your target, allowing you more kills and better items than them early on.

Greater Glyph of Magic Resist- Same for these, usually at least one the enemy ADC or Support has a skill that does magic damage, these well help you last longer and hopefully let you take out your target before they can do enough damage to you.

Greater Quintessence of Health- The extra 78 health actually does matter a lot early game, (compared to 108 late game) and the extra 13.5 attack damage you would get from Greater Quintessence of Attack Damage, doesn't stand up to the extra survivalbility.

Why I recommend Health Quints over Attack Quints:
If, lets say, you're both the same champion, 78/13.5 = 5.7, you last about 6 more basic attacks than they do which is more than enough to take them out.
You should last even longer than another 6 hits against you because you also have Greater Seal of Armor and you while you last longer, your also shredding through their armor with Greater Mark of Armor Penetration.

I recommend going 21/9/0.

I usually go with one of three different combinations.

Balanced

Offense

Defense

(Mobility + Damage) (Balance)

(Weaken + Damage) (Offense)

(Support + Damage) (Defense)

Flash- for escaping, and going for the kill. Ignite- for extra DoT damage, stopping them from healing, and for the extra 5 attack damage on cooldown.

Exhaust- to slow them down and Nerf them completely, weaken their armor and magic resist, and go in for the kill. Ignite- for extra DoT damage, stopping them from healing, and for the extra 5 attack damage on cooldown.

Heal for more survivalbility, helping your team, saving you from last second ignite/poison/bleed, and staying in lane. Ignite- for extra DoT damage, stopping them from healing, and for the extra 5 attack damage on cooldown.

Don't be stingy with Exhaust, Ignite, or Heal, the longer they're not on cooldown, the less times you'll use them in each game.

Blinding Assault(Q)- I recommend getting it first for harass and blind early game. I put emphasis on blind because it increases your survivability. I also prefer maxing Blinding Assault(Q) first because not only is it your most damaging skill-shot, it also blinds the enemy and should be used most often.

Vault(E)- Second because it allows more harass early game and is more of a utility skill because it doesn't make you invulnerable during the animation. I max Vault(E) second because not only does it do damage, it applies Harrier which lets you do even more damage.

Heightened Senses(W)- I get this third because you wont be needing the attack speed right away since you'll be using your skills often and later Phantom Dancer to get attack speed; though its still useful for revealing the surrounding area. Max Heightened Senses(W) last, as sending out valor for auto attacking is not highly recommended early on; you should be using your skills as Valor also.

Tag team Tag Team(R)- Get this as soon as possible because you never know when the extra mobility will come in handy. Early game its useful to catch up to an escaping target or to just use Skystrike to get secure a kill or just do a bit of extra damage while Quinn's skills are on cooldown. Max it third for obvious reasons.

For better understanding of this part of the guide you can look at the item sequence near the top of this guide, I've laid out what to get and when to get it in order as to help you see it visually.

Here is what the final build will look like in this order.
I recommend staring out with a Long Sword and two Health Potions because you'll want the extra damage and HP at the start of the game, over the small amount of speed boots will give you.

Work towards Bloodthirster first because of its nice +70 Attack Damage and its 12% Lifesteal (+100/+18% stacked). For Quinn this is better than Blade of the Ruined King because you'll want the extra 45 Attack Damage for your basic attacks and for your skills.
(Of course Mid to late game if they have a high HP Tank like Cho'gath, Shen, Singed, etc, your free to also get a Blade of the Ruined King. Just make sure to get your Warmog's Armor first.)

Next get your Boots, and work towards a Zeal.

After your Zeal upgrade your boots (I recommend Mobility Boots) and work towards upgrading your Zeal into a Phantom Dancer. The Phantom Dancer will give you the extra Attack Speed and add to your movement speed, while of course landing you hard hitting critical hits.

By the middle of mid game you should now be working towards your Warmog's Armor, get the Giant's Belt first then the Ruby Crystal. By or at the end of mid game you should have your Warmog's Armor built and should be able to now use Valor more for his Heightened Senses (increasing attack speed) Attacks, of course after you have already used his skills on your target(s).

Next Build an Infinity Edge, getting the B. F. Sword first, to do more damage and make more use of your critical hits (especially with Valor's basic attacks).

Lastly, pick up a Guardian Angel, I recommend getting the Chain Vest first, this will allow you a second chance if the enemy team focuses you first, (They usually will) then while you revive with it, your team should be doing better and allow you to get back in the fight (or escape if you need to).

As for boot enchantments go, you can get whichever one you like. I feel they all come in handy based on the situation. As for when to get one, that's usually based on user preference.

Enchantment: Captain- If you're trying to push or are still laning when you decide to get an enchantment.

Enchantment: Homeguard- If your team is defending in the base.

Enchantment: Furor- If you're in non of the above situations or if you're having issues securing kills

Enchantment: Alacrity- If you're in none of those situations but you do not have Mobility Boots or Boots of Swiftness.

Thanks for reading.

Let me just add that surviving longer means dealing more damage, having more time to take out your enemies, and heal yourself with lifesteal. You can't do any of that if your target takes you out in only 1-3 skills or hits.

Surviving is everything, it means more kills and gold for you, and less kills and gold for your enemies.

Again, thanks for reading.