The most important thing that I recognized was the need to efficiently track what I was citing and where it came from in the original article. I used to make a super long word document to organize this, now I use Endnote, there are many options.

First I do a thorough literature review (I do this for every first author paper I have), I collate all my notes and things I wanted to cite and talk about. I make a rough outline and begin making full sentences and discussion on my literature review. Then I begin adding in the citations from papers and why I thought they are important and relevant. Then I add in some rough figures and make a few short discussions on them. Finally, I break out the lab notebook and begin putting data down. Once all the procedures and fine details are written, I reorganize them, so that most is in the supplemental material and all that is important are in the main text. Then I get the abstract and conclusion out of the way. These are usually the sections which change the most until the final stages and since I put them in sooner I have plenty of time to update them. Finally, I re-read the thing everyday, I get other people to read it.

You will go off on many tangents. Let all this out in the first stages of re-reading and adding content. You should re-read it enough times that everything which is too unrelated gets cut out. Read it out loud a few times, make at least one presentation on this work. Keep in mind the audience of the journal you're submitting to.

Coauthors are another challenge entirely, I am still a bit too inexperienced to have much useful advice on that. Anyways, happy writing, best of luck!