In my opinion, if you are on a journey to overhaul, or even just refine, your personal style, the FIRST thing you should do is figure out your personal color palette. Not just your color season, but a personalized set of colors that are unique to you. The traditional color seasons, while helpful, are just too broad to make the kind of impact I'm talking about here. Using Zyla's system and finding my "True Colors" (as he calls them) has had more of an impact on my wardrobe, my style, and my confidence in my choices than anything else.
What is the Zyla Color System?
This color analysis is based on the colors that are actually present in your skin, hair, veins, etc. But if you think that means your palette will consist of all beiges, browns, and maybe some blues and greens, think again! It is truly astounding how many variations and shades of colors you have on your body, and this system helps you identify them and translate them into not only your wardrobe but also your decor.
The colors that come from different areas of your body can be used strategically in various ways depending on the effect you want to achieve or how you want to feel. For example, your Essence color, which is a color that harmonizes all of the base tones of your skin, is a very personal shade that is good for restful areas, yoga clothes, or for anytime you want to be honest and vulnerable. On the flip side, this is NOT the color to wear in an intense situation like a stage performance or a job interview! That could leave you feeling far too raw and exposed.

Zyla's goal is to help you achieve beauty that comes—not from any set of external standards—but from within, as an expression of yourself.
You don't have to:
Lose weight
Wear a lot of makeup
Be a slave to fashion trends
Since implementing this color system, I wear less makeup, spend less money on clothes, and generally feel more confident and comfortable in my clothing. Yes, color really can do that for you.
Having a color palette also makes shopping so much faster and more efficient! I don't have to comb through racks of clothes—I just hone right in on those items that already fit my color palette, then evaluate them for style (i.e. essence), lines (i.e. Kibbe), and fit (in that order). If the item meets all 4 criteria, it comes home with me. If not, I leave it for someone else to enjoy.
Finding Your Colors
Humans can differentiate between up to 10 million subtleties in colors! These variations might be a function of Saturation, Value, Tint, Shade, Tone, Temperature, or any combination thereof. Because of this, your personal best colors can be pretty darn specific. For example, this shade and value of citron flatters me:

But this one does not:

The saturation, value, and color temperature of the second sweater are all wrong for me, even though both items are technically similar colors.
This is why it is helpful to keep a color reference card (physical or digital) on you at all times!
How to really see color
Practice looking beyond and around the color name. Yes, an item of clothing may be "red". But is it a true red? Or is it more of a pink, purple, orange, or brown toned red?

Or let's say you know that you want a pink-toned red. Should it be more strawberry pink, watermelon pink, or perhaps geranium pink?

If you know that you are flattered by orange reds, is your ideal shade tangerine, brick red, cayenne...or something else?
Hopefully, you're beginning to see how important specificity is here. As an example, compare a general Light Summer color palette (which is the color season I personally fall into) to my personalized Zyla color palette:


There is definitely some overlap. The Salmon pink is spot on, and the Spruce and Steel Blue are pretty close. But Dusty Purple looks downright awful on me; I need the depth of an Aubergine. And that version of Cocoa Brown makes my skin read very sallow, as opposed to my Dark Sepia Brown. So as you can see, color seasons can get you close, but close has just never been good enough for me, not when it comes to color. It has to be just right.
(Note: I am an Iridescent Summer in Zyla's system, but my unique palette is even more personalized and specific than that. It is rare for your personal palette to look exactly like anyone else's.)
This is a very brief overview of the system. If you are interested in color and have enjoyed the discussion thus far, I highly recommend picking up your own copy of Zyla's book. If you find yourself losing patience with all of this color madness or are just having a hard time seeing all of the different shades and tones within yourself (which is totally understandable—it is often hardest to analyze ourselves clearly) I do offer online color analysis.
These are so much fun to do and the results can be really eye opening. Either way, I hope you enjoy exploring this system as much as I have!