I've written for a long time, and I think it's important to think hard about how writing is going to fit into your life--after all, if you do it right, writing is something that you can pursue well into old age.
Music is that way, too: You can enjoy music in all sorts of ways throughout your life, and you can do that without ever becoming a full-time professional musician. You can be a doctor who sings bass in a variety of choirs, as was my father, and no one blinks an eye at it.
There seems to be a resistance to approaching writing that way, I assume because of the myth that getting published is some marker of quality. And since self-publishing has rather suddenly begun to offer the possibility of turning writing into lucrative full-time work, people think that they must exploit that possibility. They feel like they gotta do their damnest to hit the jackpot. They gotta write write write write write write!!! and they gotta promote the hell out of everything all the time! Including when they're writing! You just write with your right hand and tweet with your left--don't be a slacker!!!
And don't do anything else! You have no other interests now--you're a writer! You can't possibly expect to get anywhere if, say, you're a doctor who, instead of singing bass in choirs, writes poetry in your spare time. That's just crazy: You can only be one thing!
There was a time where that kind of insane focus was totally necessary--go back and read some of Joe Konrath's pre-self-publishing posts if you don't believe me. But that time is past, and clearly it was yet another symptom of how dysfunctional publishing had become--it's not like things were going swimmingly for Konrath despite all his work.
The problem with the old paradigm was, you either had to sell like crazy, or you had no career whatsoever--your books would never see the light of day. For Konrath, it was scramble or die. But nowadays, if you're not a bestseller, so what? If your book just trundles along, occasionally selling a copy here and there (or not), it's not going to kill you. No one is going to stop you from publishing your next book because your current one isn't selling--believe me, if that was the case, Trust would never have come out.
The other thing is, in the old days, when a book had only a few months to make it, it made sense to scramble to promote it for that short period of time. But now there are no limits to shelf space, and no time limits on your book. So if you're scrambling, there's no end to it. E-books are forever. You will burn out long before your book ever leaves the store.
Which means you need to think long and hard about what you "have" to do to promote, since you'll be doing it for the foreseeable future. The thing I really like about Lindsay Buroker's approach is that she molds tasks to her own personal preferences--she doesn't spend huge hunks of her time doing unrewarding stuff just because someone else told her she has to. There's stuff she hires out, there's stuff she does in the most-efficient way possible, there's stuff she does in her own way, and there's stuff she just does not do, because she's not comfortable doing it. She always looks at these tasks through that paradigm: Do I want to be doing this?
Even writing tons of books--the go-to approach for people who don't like marketing--is only worth doing if you enjoy writing tons of books. Maybe you don't want to do nothing but write all day. Maybe you only have an idea for one book. Maybe you actually enjoy what other people sneeringly call your "day job." I've always preferred freelancing to regular full-time work, but mine is by no means the only way: Despite his fame, Harvey Pekar never left his dead-end job as a file clerk until he retired. His job didn't interfere with his art, and the structure of it helped keep him sane, so he sensibly held onto it.
We get it drummed into our heads that we have to have ambition, that we need to grab that brass ring, that when opportunity knocks, we'd damned well answer the door. What doesn't get mentioned is that after you get that brass ring and open that door, you still have to live your life. You're still you, and you can still be made miserable if you're not careful. Publishing has gotten a lot more flexible; there's no point in ruining that with your own rigid expectations.