I personally find that having a couple of projects going at once can be an aid to focus, refreshing my brain as I go back and forth between them – a book review and a novel at the same time, for example. But I’ve seen that writers who are starting out sometimes throw their energy in so many different directions that they can never finish any of the projects, much less all of them.To me a good test is this: what do you like to read? What kind of book moves and affects you the most? Is it the memoir, the novel, the long poem-collection? Personally, I find myself most immersed in the novel, and that’s why I write them – they have the most magic for me. The joy of self-expression is exhilarating, but ultimately choosing one venue for it can make your work much better – and same for your chances of actually finishing something.