When I first started writing, I really didn't know what I was doing, and I blissfully enjoyed the process of stumbling about in fictional realms. I didn't worry about the business side of writing, about the things beyond writing quality that might influence whether a story could be sold: length, trends, unpopular tropes ...
And then I did worry about these things. Not so much the trends part of it - I was never all that enthused about trying to find the latest wave to ride. But length, particularly when it came to short fiction, and other elements that publishers / editors hunted for? These things bedeviled me. I pushed aside projects I thought about writing because I didn't think they would be able to sell. When my short fiction crossed certain word thresholds - and it often did; I am, after all, a novelist at heart - I would get depressed and even angry with myself. What was the point?
Recently, I've turned a corner. I've decided I'm done worrying. Partly this is because I have enough of a backlog that I'm not under pressure to produce new work with an eye towards sales (editing is another story, mind). But mainly, I want to keep hold of that crazy joy at the heart of writing; I don't want to lose the simple enjoyment of it. This is what motivated me to write my zombie novella, even though the genre is done to death and works of this length are a horror to sell: I just thought it would be a blast to write. And it was. It was the most sheer fun I'd had writing anything in a long time.
But even as I prepare to goof off, there's something else I need to give myself permission to do: pick projects that seem like a stretch for my skill level, that are difficult to pull off, that present challenges I have to think my way through. Scylla and Charybdis was just such a project, for me - novel-length science fiction being out of my comfort zone - and I gave the foundation work more love and attention than usual. Look where it ended up.
So I am resolved: let the games begin.