What not to worry about when you submit your paper

When I was a graduate student, I used to really worry about the little details of manuscripts when submitting a new paper, like whether it fits in the length requirements or specific figure lettering requirements or how the figures might fit on a page or whatever. I think I know why: it felt like something I could control in an otherwise very opaque and essentially random process. I now think it really just doesn't matter. Yes, try and keep to the basic spirit of the journal (a 50 page treatise on the mathematical details of burst modeling probably doesn't belong at Science), and get some very basic things right like citation formatting, but beyond that, don't sweat the length limits and so forth. Your job at this stage is to convince the editors that it's interesting and to convince the reviewers that its interesting and sound. Reviewers rarely read the supplement, so I when in doubt, put it in the main figure. If you're lucky enough to get your paper accepted or close to it, then great! Now you can worry about all those details, hopefully with some help from the editors.

So write clearly and compellingly, make attractive and easy to parse figures, and don't worry about the small stuff. Hopefully, you'll have plenty of time for that later!