I've got some more things to say. Once again, some of it won't be very popular, but I believe it to be true. Better you hear it from me than find out on your own.
1: Embrace the suck
This is army speak for the inevitability of ending up in a situation that sucks, and the attitude that will see you through it. Complaining, time honored though it may be, will not extricate you from the suck. Pretending you are not in the suck will not extricate you from the suck. Flailing around in a panic will definitely not get your suck-stuck behind out of the suck. What will extricate you from the suck is realizing and admitting that you are mired in suckitude, plotting a course to get away from the suck, and then implementing your plan. This is true whether you are a self publisher or traditionally published.
Wow, I don't think I've written the word 'suck' that many times ever.
2: Talk is cheap
Whether it's a publisher, an agent, or a so-called indie publishing expert that you're listening to, remain skeptical. They are in the business of making money from your books. They will say what you want to hear, and it'll sound really good. Just like your prom date. Yeah, exactly. We all know how that turned out.
The point here: get it in writing, and make sure you understand what it says, and what it means, before you agree to anything. Also remember that money should flow to the author in all traditional publishing scenarios. If you're an indie and money is leaving your bank account, it had better do so for specific reasons with measurable outcomes. For example, a book cover.
3: People love to make excuses
You know what? Crappy things happen to people. They miss deadlines. It's an imperfect world. I get that. But you are not immortal. Your time on this earth is finite. And people who constantly make excuses for failing to live up to agreements are stealing your time.
Scrape them off.
4: Don't be a cheap talker or an excuse maker
You want publishing success, however you define it? You are ultimately responsible for making it happen. Treat others, and especially yourself, with the same respect you want to be given. Don't make excuses that you have no time to write if you just binge-watched Luke Cake or Downton Abbey. Don't throw up your hands and say you don't know where to start if you have access to Google. And don't call yourself a writer if you keep polishing the same 1/3 of a manuscript over and over for months or years.
Yeah, this writing thing is hard. See point 1 above. It's first for a reason – because it will get you through everything else that happens to you along the way.
Give the Suck a big ole hug, and get writing.