Describing A Description

Yesterday on Twitter I mentioned (sarcastically, of course) how I love when writers have their protagonists look at themselves in a mirror so the reader can get a description of what that particular character looks like. Lazy storytelling or convenient storytelling? Either way, I know I've been guilty of it. But then I wondered how does one go about describing a protagonist when the book is seen only through that protagonist's point of view? Oftentimes in books that deal with multiple POVs you might find a secondary character seeing the protag for the first time, and then there goes your description. But even that seems like lazy and convenient storytelling.

And then I wondered does the reader really even need to know what the protagonist looks like? Maybe. If it's crucial to the plot, I guess so. Thinking over all the books I've read, very rarely am I given an exact description of a protagonist. And if I am given one, oftentimes that description is muddled with my preconceived notion of what the character already looks like.

I'm not talking about characters in short stories. Very rarely are we given a description of the main character in stories, and when we do it's for a good reason ... or at least it should be a good reason.

So what, exactly, is the best way to describe your protagonist without seeming lazy?

Or, better yet, is it possible to pull off lazy techniques if they're done well?

This last question puts me in mind of Orson Welles's Touch of Evil. One of the legends of the film is Welles -- being the crazy genius that he was -- asked a producer to give him the very worst script available to prove that he could make a great film from an awful script. And while Touch of Evil may not be the greatest film ever made, it certainly has its moments all thanks to Welles.

So I wonder even if you have your protagonist look at himself or herself in the mirror so the reader can get a description of what they look like -- if you pull it off masterly so that the reader barely even notices, is it still considered lazy storytelling?