The essential thing I do, every day (maybe six days a week, maybe seven), is write. I write original pages, and I write revisions of existing pages. That is the core and necessary part of what I do.
I do a lot of other stuff in my quest, as Indiana Jones would have it, for fortune and glory. I network. I read and comment on stuff by the Story Monkeys. I read and comment on stuff by other writers. I write query letters. I talk to my agent about revisions, or about how it's going with publishers. I read the Publisher's Market daily deal e-mail for a market update. I go to bookstores and browse the shelves. I read in my target audience. I read David Farland's Daily Kick, and the blogs of other writers. I write this blog. I attend conventions. Those are all good things.
But no amount of writing this blog or reading the daily deals will generate a book. All that stuff is good and important, but unless I do the essential thing -- write -- it's pointless.
So I don't ever let myself off the hook by saying "I didn't write today, but I did put together a query letter," or "I didn't write today, but I did some good market research." That way lies frustration, barrenness and the death of writing.
Don't you do it, either.