[image courtesy: Flickr Creative Commons, MonkeyMyshkin - these aren't my toes!]
The joy of describing physical attributes.
Every face tells a story, as does every toe, wrist and earlobe.
Describing characters can be a lot of fun, and it's something I personally think you can never be too good at!
Generally speaking, when someone describes a character it's their expression, eyes, lips, cheekbones and hair, then a vague description of height and stature (or something in that order). This is obviously an essential part of character development, but no less important is the the random insertion of one or two 'other' physical traits. The the narrow fragility of a heroine's wrist, for example, might be a nice way to reflect her sensitive nature, or the stretched material over your hero's broad back can similarly reflect his inner strength. Good descriptions of physical traits can also help you develop an unusual aspect of the main character as well. Eyebrows are particularly good for this. For example, your heroine may have strong dark angular eyebrows that arch above hard assessing eyes.
When describing your hero/heroine it is generally the attractive characteristics that are mentioned first (especially in true romance writing - no one wants to read about a hero with stubby fingers, or hairy toes. Nor will they feel affection for a heroine with outrageous eczema or earlobes the size of lamb steaks). Romantic main characters are generally attractive - they may have quirks and oddities, or even be a bit "chubby" or "plain", but rarely are they significantly physically flawed - you can leave that for the subcharacters!
I seriously love an interesting physical flaw thrown around in a book. Whether it be front teeth that overlap like a doll crossing its legs, or square nostrils - these attributes are fascinating and utterly memorable - when in the correct context. Quirky oddities won't suit some styles of writing, unless inserted with great thought and sensitivity.
In my writing, I like to use physical characteristics that enhance the personality of the character. That's not to say just by looking at the physical characteristics of a character you can deduce their personality - because we all know that sometimes the most beautiful person on the outside can be an utter monster inside. Little physical descriptions can hint, or expand, on something you know or do not about the character, and used with care and intelligence help create a character that will live in your memory long after the book has closed.