style guide

Stuff about proper branding. Most stuff is from the exquisite Dropbox branding site. They only use 4 colors and are super memorable! Link's below.

Logo

logotype         text + image    use whenever possible
glyph            image           use in UI with limited space
vertical lockup  text + image    use only in marketing with limited space
outline          image           use in UI with limited space

A small disclaimer below that from the dropbox site, note the tone of voice:

Thanks for not editing, changing, distorting, recoloring, or reconfiguring the logo.

Logo colors

color        white background   most used
white        dark background    used on darker backgrounds
dark grey    white background   sparingly used

There dropbox goes again:

Thanks for not embellishing on the logo with shadows, patterns, intricate backgrounds, or elaborate gold jewelry.

Brandname colors

Emphasis on who's colors it is. Explain what you're looking at:

White canvases and cool grey copy splashed with accents of Dropbox blue.

Work should be of a color rectangle with:

the color name
if bg color give a border, else no border
hex code of the color
if used for print also include cmyk and pantone

Spacing considerations

bunch 'o' text about the usage
visual examples with the margins laid out
technical, but damn important
yes, this is part of a designers job

In writing

Have a single correct writing
Explain the gotchas in text
Show examples of how it's not done

From the Dropbox website:

Write Dropbox in plain text rather than embedding the logo into text

Solid.

Screenshots

Explain what you're allowed to do legally (e.g. "feel free to use")
Explain what you shouldn't do to screenshots
Provide a bunch of quality screenshots in the press kit

Use of the materials

Here comes a whole slew of examples that probably cover your use case.

In general
Advertising, promotional, and sales materials
Education and instruction (books, guides, publications, and conferences)
Products, websites, names and logos
Functional Uses (UIs / buttons)
Linking to Dropbox
Merchandise
More questions? (and include screenshots so we can judge faster) (also don't assume no answer = we agreed to whatever you're planning)

styleguide