Thanks Mathias and Argyle!
I've spent the past 3 years or so working predominantly in illustrator as a profession, so I've had a lot of time to work up my skill level as well as establish a sound work flow. Because of this, that level of madness one would expect from working on such a piece is not really there. One thing I've learned about working in vector is that a lot of the techniques you learn from pixel art still apply. This is especially true when working in fine detail where things can get muddied very easily. A strong grasp of pixel art translates perfectly to these scenarios, because even though the shapes are vectors the laws of pixel art stay true. Meaning that you have to understand how complex shapes are going to be translated on the pixel level when the image is fully zoomed out. With this knowledge you can do some pretty cool stuff with shapes that operate on the sub-pixel level, for instance a triangle that ends in a very narrow point which is maybe 2 pixels at its thickest will create a smooth gradient that seems to extend from a small 1 or 2 pixel base. In the face on this piece especially I applied that knowledge to get a very painterly effect although zoomed it appears nothing like that. Here's a zoomed image of the face so you can see what I'm talking about.
The secret to getting fast and efficient with illustrator is 1) obviously knowing shortcuts and 2) becoming intimate with the pen tool as well as the direct select tool. When you can draw faster with the pen tool than you can do with your hands, then you know you're getting somewhere. Here is a rundown of my most commonly used shortcuts and their application.
[P] The Pen Tool
Absolutely the most important tool you'll ever use in Illustrator
[A] Direct Select Arrow
Extremely useful for fine-tuning your initial line work that you've laid down with the pen tool.
[-B-] Brush Tool
With this you can sketch out the basic foundation of your line work before you even start using the pen tool. This is actually very valuable and can save a lot of time if you rough something in on a lower layer before you start drawing the lines with your pen tool.
[Ctrl + G/Ctrl + Shift + G] Group and Ungroup
Another critical command. Nothing speeds up your work better than being able to group and ungroup specific areas as they become the focus of your efforts or not.
[V] Select Arrow
Just putting it in there so you don't think it's not important. Great for moving around grouped objects. Selecting an object or group of objects while holding shift will either select or deselect them based on their current state. If it's selected it will be deselected and vice-versa.
[ctrl + 2/ctrl + alt + 2] Paste to Artboard
Not sure what the actual term for this is, but I only learned it recently. With this you can make whatever you have selected unselectable by pressing ctrl+2. Adding alt into the mix releases it form this state of non-editability. The funky thing is that you can make all sorts of things uneditable, but everything gets released at the same time no matter what. Very useful when there's just too many lines and objects in your way.
[-I-] Eyedropper
Of course there is much value to be had with this tool.
[Ctrl+F] Paste in Front
This is of exceptional value when dealing with so many shapes all on the same layer. With this you can select an object in the layering hierarchy that is in a position you'd like another object to be in and then paste in front. Now that shape will be just above that object in the layering order. Even cooler is that you can direct select an object within a set of grouped objects, paste in front, and the object you pasted will automatically be part of that group right where you want it to be.
[Ctrl + [ and ] ] Bring Forward/Backward
This shortcut is used to send objects one step forward or backward. Using this with shift will move them all the way to the front or back. This is great to use in conjunction with paste in front, specifically when you have transparent objects that cover the entirety of the objects beneath it, but want to send something just below that transparent object. Just cut/copy the object you want, select the transparent object that's in your way, paste in front, and then send backward once. Learning to manipulate paste in front and bring forward/backward is one of the greatest ways you can increase your work flow. In illustrator there will be countless times where you have to deal with layering issues, and these few commands basically solve all of them. The direct select tool is also useful in this regard when dealing with grouped shapes that you want to incorporate objects into.
Hopefully some of that was helpful for whoever is interested in improving their work flow in illustrator. Illustrator can be a really fast and friendly program, but it is more important than most programs to best know how to navigate it and the art board as so much relies on the layering and grouping of objects and the ways they interact.