Thanks a lot for this feedback and I love you because of this. I'll take lots if this information and put it in the guide if that's okay. I highly respect you for taking your time to write this comment. You made lots of good points that really helps, so, thanks, Kafurflgig! :3

EDIT: One more thing, I prefer Black Cleaver over Last Whisper because of the health and cooldown reduction. I feel like it covers up for the fact that I play Quinn without any defensive items.

For your build I have two main concerns:

First off, you've forgotten to add any sort of defensive alternatives. On any carry you need this to avoid getting killed immediately as you are seen as the major damage threat.

You've built 3 sources of crit, two of which are fairly major, yet you haven't build an Infinity Edge. It gives you massive AD and really helps support your crits. I'd probably remove two of those crit items (preferably the PD and Tri Force) and then replace them with the one IE so you have more room for defense and still get the bonus to your crits.

As for the rest, you might want to take Last Whisper over the Cleaver in most cases. It's far cheaper and the armor pen scales a lot better than Cleaver.

Might want all flat AD Quints. Lifesteal quints got nerfed pretty bad and especially when you're not starting off with lot of AD they'll be a lot weaker for you.

Try Doran's Blade to start, it gives you a good mix of all the things you want in lane.

Try 21/9/0 masteries, defense is usually better to have on ADC as you tend to trade often and get dived on early on in the game. She's one of the few that does have an escape, but it'll still help out trade many bruisers.

W does have nice utility in the active, but it also has a lot in it's Passive as well. Maxing your W second is actually really strong. The bonus attack speed in both forms is actually really nice to have and can help you get off a lot more damage than the one harrier proc of vault you'd have anyways. Just something to consider.

You'll want to have sections of your guide explaining the build so people understand why certain items are strong. This is especially helpful with newer players who don't yet understand a lot about building Quinn or just about items in general.

For your title you might want something clearer like "Season 4 Quinn Top" just to distinguish your guide from other Quinn guides.