I could not figure out the structure of the NEWS file, so if someone
can explain it, I'll add something there also.
NEWS should be edited in Outline Mode. The "**", "***", etc. prefixes
mark sections and subsections. We try to arrange things so that more
important changes come first (I think GTK support is one of the more
important ones). User-level and Lisp-level changes are described
separately (there's a header for Lisp changes that precedes the Lisp
section). The "+++" and "---" markers before the NEWS items are
explained at the beginning of the file.
Is there anything else you don't understand? If so, please ask specific
questions.