I had a thought one day and then it became this.
Note: These are just guidelines/things to think about in your life/publishing adventures. They are meant to be both serious and a little silly (the advice is serious but presented in an Alex way).
1. You will disagree with your editor/an edit at least once. Likely more.
That's fine--as long as you and the editor can discuss it like civil human beings. If an edit/comment makes you upset, then just pass by it at first. Take some time to consider it, then re-evaluate. It keeps tempers calm when the trigger could just be a misunderstanding. The editor just wants to make this book the best it can be, but the editor is also human. It could be a misunderstanding, the editor could be seeing a different vision than you meant, the editor could have just misread something and just needs that pointed out. The editor could be stating it in a way that pushes your buttons, while the editor is completely unaware of how you're reading it.
But, also, this is your book. Stand up for what you want to keep, whether it's for voice or flow or preference. However, keep in mind that editors have some experience, so listen to what they say and then decide. Don't, for instance, decide that the serial comma needs to die in a fire and be unwilling to change no matter what.
2. No matter how many eyes see it, the book will be published with at least one error/typo.
I'm pretty sure this is a law of reality or something. The longer the work, the increased the likelihood one (or more) will show up. Don't be angry. Just come to terms with this reality. Most readers will skip over it without even noticing it. If your publishers is amenable, feel free to let them know about the typo.
3. Writing is hard.
Not always, but sometimes. You probably already knew this.
4. Editing is hard.
You usually send to a publisher with a vague idea that this book is really good and finished and ready. Then they send back notes, whether in rejection or during revisions, and you realize your precious baby wasn't perfect. And you get several rounds of this, to the point where it's just wounds on top of wounds. (See back to point 1.)
This doesn't happen every time of course, but if you go in with the mindset that it's OK if your words are going to get poked at--sometimes hard--then it'll make it an easier journey.
5. Publishing is hard.
In some ways that feels like it should be the end. But then there's marketing and PR and unless you hire a publicity person for yourself, you have to take care of it. Even if the publisher has a marketing department, they aren't your personal slaves and you have to be out there and working it. The great thing about social media is you get to be out there! The bad thing about social media is you have to be out there! Obviously you can choose not to, but you'll be doing yourself (and your book) a disservice.
6. Read your contract.
Every time you have to sign a new one, read it. Every publisher will be different and even the same publisher will make changes over time. Know what you're getting into. Don't be afraid to ask for changes--the publisher can always say no, and it won't result in them pulling the contract. You then just have to decide if you still want to sign. Don't be afraid to ask if you're confused about something. If you don't trust the publisher to tell you what it means (which should be a warning sign...), then google, ask friends, ask Twitter. It's important, don't feel (too) rushed.
There are lots of other points I haven't covered here, and I didn't cover any of them in depth, but this is just to get you thinking about your place in the process.