I am still struggling to find a good naming convention for assets like images, js and css files used in my web projects.
So, my current would be:
CSS:
The BBC have tons of standards relating web development.
Their standard is fairly simple for CSS files:
http://www.bbc.co.uk/guidelines/futuremedia/technical/css.shtml
You might be able to find something useful on their main site:
http://www.bbc.co.uk/guidelines/futuremedia/