[electrondood]

Speak directly to, not over, the audience. Like, as if you're teaching a friend how to use what you built.

Throw in some humor. Avoid any unnecessary hoidy-toidy or pretentious language.

[junon]

Agreed except for the humor bit. Please don't include humor in technical writing.

The rule of thumb I learned was "avoid anything that ends in -ly" (there are exceptions, but this has always been a good rule).