not sure but here is an idea and a question
I think it might help to try to answer in your project outcome statement what, when, where you/others will know that the [project is done and done right.
I did not do this when I made the error of confusing a higher level intention with a project. For example, I defined a project as "make sure that my mother was humanely treated in the nursing home." In fact that was not really a project but a guiding value that translated into several projects: visit 2x/week; attend care conferences; colaborate with other visitors to monitor her situation; provide her with art, food and music that she liked. And another guiding value would have been, "preserve my mental health while mother is in nursing home", which would then be translated into several specific projects for taking care of myself.
I think the first question is "does this have more than one step?, then draft a statement answering the who, waht, when kinds of questions, then ask is this more than one project? But, I have not figured out what questions to ask to determine how to break a project down to subprojects. It seems that one needs to have a lot of knowledge of the content area of a project to do this, experience, and a good analytic mind. But maybe there are some questions or guidelines to ask yourself to determine this.