Vigorous writing is concise. A sentence should contain no unnecessary words, a paragraph no unnecessary sentences, for the same reason that a drawing should have no unnecessary lines and a machine no unnecessary parts.
William Strunk, Jr., The Elements of Style, 1918
Personally, I prefer collaborative article writing in distinct stages. After agreeing on writing the paper and agreeing on the overall content, someone does the outline, then the different sections are fleshed out and each co-author gets specific sections to write. One person (the first author) is responsible for the whole thing and has to integrate the text and smooth it over.
However, you might prefer a synchronous writing mode. One text in a central location that is edited by all authors (roughly) at the same time. You can use GoogleDocs for this kind of writing. However, I recently got an eMail pointing me to Authorea. It seems to be made for collaborative writing. Instead of everyone being able to edit everything, Authorea seems to lock down paragraphs. Makes sense.
The developers write:
Authorea […] an online platform for writing, discussing, collaborating on, and sharing academic papers.
Authorea was created by a group of astro/experimental physicists and is a mix of GitHub and Google Docs for scientists. It enables them to work together on projects and create a paper of the future – a living Git repository that connects text, code, graphics, data, and notebooks (like IPhyton that allows to launch data ecosystem).
To simplify paper submission process, we added over 8000 different journal templates (following correct citation guidelines) – students and researchers can use them as a format for their papers. We also have templates for grant proposals, student papers, and theses (if something is missing you can ping us and we will upload it).
I haven’t tested it (currently not writing collaborative documents and for my writing I prefer Scrivener) but it might be worth a look if you have to write something with multiple people at the same time.
If you have tested Authorea, I’d love to hear from you.