You know the big rocks of publishing a debut novel. Write it, edit it, market it, get it into ARC readers' hands. Every writing group and craft book will drill that into you.
What they don't spend much time on is the pile of smaller tasks sitting underneath those big rocks, the ones with their own timelines, their own quirks, and their own ways of ruining your launch week if you leave them until launch week. None of these are hard. Most of them are just easy to forget, because nobody puts them on the syllabus. Here's the list we hand to authors getting close to their pub date.
Get your ISBNs from Bowker, if you want to own them. In the US, Bowker (myidentifiers.com) is the only official source. A single ISBN runs $125, which is a bad deal the moment you need more than one. A 10-pack is $295, or about $30 each, and you'll burn through more ISBNs than you expect once you count paperback, hardcover, and ebook editions separately. One thing to skip: Bowker will try to sell you a barcode for $25 on top of the ISBN. Don't pay it. You'll get a barcode for free the moment you upload your book to KDP, IngramSpark, or Cabins Press.
Claim your author profiles early, especially Goodreads. Adding your book and claiming your Goodreads author account is one of those processes that feels like it was designed in 2007, because it was. Submitting the request, getting verified, and having your book linked to your profile can take days to weeks, with no clear timeline. Do this the moment you have a title and cover, not the week before launch, so readers have time to add your book to their TBR before it's actually out. Do the same on StoryGraph and Fable while you're at it. Neither takes long, and both have readers who will never find you on Goodreads.
Set up your publishing platform accounts before you need them. If you're going wide or exclusive through Amazon KDP, or working with print distribution through IngramSpark, get the account created and verified early. Amazon has a habit of suspending author accounts with little warning and even less explanation, and appeals can take weeks. IngramSpark's setup flow is notoriously fiddly. If you can, have someone who's done it before walk you through it, or at least budget more patience than you think you'll need. Neither platform rewards doing this at the last minute.
Book your events well ahead of your launch date. If you want festival appearances or signings tied to your release, start looking now. The larger festivals open vendor registration six months or more before the event, and popular slots fill fast. If your release date is fixed, work backward from it and treat event applications like a deadline, not a someday task.
Order your print copies at least a month before any event. Printers and distributors have their own lead times, and "a month" assumes nothing goes wrong. Something usually goes wrong. Build in a buffer so a shipping delay doesn't mean showing up to your own event with nothing to sell.
Decide how you're managing your ARC campaign before you need readers. Are you handling applications through a spreadsheet and a Google Form, or a dedicated ARC tool that tracks downloads and sends your sequence automatically? Figure this out before you start recruiting, not after your inbox fills with sign-ups you have no system for tracking. (We've written before about building an ARC funnel and designing ARC emails that don't land in spam, if you want the deeper version of this step.)
Format your manuscript for every edition you're publishing. Print formatting and ebook formatting are different jobs with different rules: trim size and margins for print, reflowable text and a working table of contents for ebook. Whether you're doing it yourself or hiring it out, this needs to happen with enough runway to catch problems, not the night before you hit publish.
Get a real copyedit, separate from your developmental edit. A developmental edit fixes your story. A copyedit catches the typos, the inconsistent hyphenation, the character whose eyes change color halfway through. Readers forgive a lot, but a book full of small errors gets called out in reviews more than almost anything else. Budget for both, and budget the time each one takes.
None of these tasks are creative work, and none of them will make or break your book on their own. But stacked together, they're the difference between a launch day that runs smoothly and one where you're scrambling to fix a Goodreads listing while your ARC readers are asking where their files are. Start this list early, and your actual launch week gets to be about the book instead of the paperwork behind it.