It is important that you keep your co-authors involved and aware of progressions within the publication process.
You may want certain coauthors to provide written contributions for your paper on specific processing. If so, be sure to
Keep them involved throughout the process! (Without bothering them incessantly! ) When you have a first draft complete and proofed by yourself, send it out. If they are good co-authors they have a
Be aware that you may get a variety of feedback, whilst it is good to listen, respect and acknowledge this - do not feel obliged to accept them
It is best to ask your co-authors for feedback once or twice during the writing process. Send them a final version and inform them you wish to submit on xxx date. This will give them an opportunity to speak out if they wish. Be sure to send out a quick email throughout as the submission process progresses.
The expectations of how long it takes to write a paper vary wildly and will be different from person to person. One thing is almost guaranteed -
Perhaps to aim for a 3 week period to get the first draft out.
From my experience, papers with extensive sections provided by co-authors can be particularly time-consuming as the article is moulded into it's final state.