I've learned there are some body type and facial feature aspects that come into play as well. For example, I'm short-waisted and somewhat busty. Long chains with interesting pendants don't work for me as they hang funny off my chest and aren't proportional on my short torso. My tall slim rectangle friend wears these beautifully. Even with regular necklace lengths I typically want a shorter chain.
I also have smaller features and at most medium contrast colouring - very little *drama* to my face if that makes any sense. Very chunky colourful statement necklaces wear me instead of the other way around. Even with earrings I can only do limited glitz.

Jules, I have the same issue you do with short waist/bustiness and can't wear the long pendant necklaces either. I have to shorten chains a lot (I often do this just by fastening the clasp higher up in the links and dropping the extra down the back of my top :P).

However, though we also share smaller features/low contrast coloring, I prefer fairly gutsy jewelry. I don't do dainty. Well, if you mean the really huge statement stuff, then yes, that can be too much. I do wear medium size earrings (vs. large or dainty), although I tend to limit actual glitz (sparkle) to more formal outfits.

(And thanks to Sharan for the kind words. For me, it feels so important to get the jewelry as close to just-right as I can! I don't always succeed, but I try.)

Jules, these very personal details are to my mind the most often-overlooked elements of style. Although we may not always notice it consciously, when we see a woman who looks "just right" in her clothes, she has related each element in her outfit directly to the particulars of her face, hair and body.

I used a stylist about ten years ago who completely transformed my style with the kind of careful analysis you show...she used my bone structure and features to take me out of delicate little chains and put me in chunky bead necklaces.

I'm continuing the analysis these days using the Inside Out Style Blog. The woman herself is no advertisement for her ideas (personal blind spot maybe?), but she is very generous with the details of how she analyses her clients to come up with those "just right" outfits.

I've looked at this chart before--thanks, Laura, for finding it again! It's helpful as a starting point. As others point out, a lot of factors can come into play besides face shape. I have a long-looking face, and I've come to feel that part of the illusion of length comes from the length from my nose to my chin. So the typical advice to long-faced women is to wear bangs, but they just cover up what I think may be a fairly average length forehead. Similarly, I think I like to wear my necklines a little higher than what Imogen's guide would suggest, perhaps because of that feature. What I do know is that when I look in the mirror, there are some necklines that just make my face seem to go on forever. I avoid those, or I shorten the expanse by filling in with a necklace. I tend to do things more on feel or what I see, than on the numbers.

Oh, and Texstyle, I have admired that necklace at Madewell! You've answered a question in my mind about it: whether the knot would stay where one put it. I may need to take the plunge and buy it!

I wear necklaces almost every day for this reason - I'm not good at the third layering piece. I feel complete though with interesting jewelry and shoes. Someone told me many years ago that the necklace should have a different shape than your shirt's neckline. I have not found this to be a universal rule but it's a good starting point for matching necklaces to necklines.

Hah, that's another reason probably will never achieve to have a minimalist wardrobe(although dreaming of one well working one all nights:-)). I realised that you cannot wear (not only) the same necklace, but neither the same shoes, bags, topper (and you name what else) to all outfits....so welcome to my world of pity:-).

lisap and Firecracker - glad you liked the Madewell necklace - I don't find it fussy at all but I do tend to play with it - I like it so much that I ordered one in silver too so I have options to go with my belt and other jewelry.