Just a quick tutorial that will help with those of you looking for a comprehensive build and simple guide.
Quinn is a splitpush marksman, good at 1v1s, roaming, and objective control.
However, she can be easily knocked out of the game as getting camped or losing lane drags her really far behind.
I like to go Lethality first, get a Youmuus and maybe a Draktkarr, Statik Shiv is really fun too and I recommend going these three items. Stuff like TriForce and Black Cleaver are good if you want a little more tank, so against true damage, and if youre against some1 like Garen or Darius, consider a Deadmans Plate. You also want to consider the enemy comp when playing and building Quinn.
The build I use is very similar to the top lane riven meta in season 5, since I use 10% cdr, 13 AD and 9 armour, Thunderlords and Ignite+ Flash. Quinn can deal surprising high amounts of damage in the first three levels, (which is why I also like to go and get Q on third level for the extra damage) so I usually take Thunders for the early game lead, if you don't get it, you don't necessarily fall behind so don't worry, yet if you want to consider team fighting more often or playing an ADC role, Warlords is a good option, Id choose it over Fervor since it gives a little more sustain, but Fervor is still a good option, as it really makes use of your passive.
If you want a little more thought or your own studies of Quinn, try;
"Godbro sama" A Challenger Quinn player, he plays a multitude of champs, but has quite a few good games on Quinn that you can learn from. EUW
"KnevîL" is also a good option, he plays Jungle and Top Quinn, currently #1 Quinn at Diamond, he seems to be a one-trick, so check him out if youre interested. EUW

Yes this is a short guide, and I apologise if youre looking for an in depth one, however its meant for people who just picked her out of the blue, or for people who want to learn her, but prefer to discover things by themselves, so the details here are fairly bare bones.