Costume Designer
Many amateur authors go to great lengths to describe what their characters are wearing. This can work better in some genres than in others, especially when the story is going to a visual medium, but
in most cases an über-detailed description isn't needed. Especially when the time of the media leap/adaptation arrives and the director designates a costume designer with his or her own ideas.
If you don't give any description of clothing, then people will assume the character is clothed in a manner that makes sense for the time, place, and the reactions of those who interact with the character. (Don't worry, they won't assume he's naked unless he's at a nudist colony.) If your character is a caveman, a pioneer, a sailor, a pirate, an astronaut, a bank teller, a CEO, a surgeon, a journalist, a harried mother... each of these carries with it some stereotype that makes you think of a certain level of clothing. You probably saw the CEO in a business suit - that's good. But since we
do make assumptions about the visuals, you as the writer have the chance to toy with us a bit, subverting our expectations in a fun or dramatic fashion.
Casting DirectorBecause of the Mary Sue backlash and the rise of "more realistic" stories, there is an increasing amount of writing about average-looking people. While this is generally good and applauded, this could deviate in several ways:
- Falling in the old dichotomy Beauty Equals Goodness Vs Ugly=Evil in an attempt to subvert this.
- The dreaded Suetiful All Along.
- Unleash the Anti-Sue.
Don't be ashamed to write about pretty people. Just don't indulge in endless sour grapes wangst, and your public will forgive you. Mostly.
If you want to avoid these problems, the recommendation is not avoiding physical descriptions entirely, but instead characterize with few elements. In fiction, a character's actions and attitudes shape their appearance; if you have a character do an evil thing and then touch their facial hair, The Reader will automatically picture a Snidely-Whiplash mustachio or a Beard of Evil. This goes for positive / good-guy characters too: you can have a character be a nice person and then let The Reader's imagination do the rest. Seriously, who's better at envisioning a character The Reader finds attractive: you or The Reader? So, give only the pertinent details, avoiding purpley adjectivation, and then leave it alone. It's better if your readers have their own mental images. Let them be the Casting Director. 
