I'm reading Fearless Creating by Eric Maisel, PhD. He breaks down the creative process into 6 stages. For each stage he describes the anxiety that must be managed, and appropriate and inappropriate ways to manage that anxiety.
Can't think of ideas? Feed yourself. Experience life, others' art, feel and think deeply.
What idea do I choose? You may have a few murky possible options. You're looking for something that feels wonderful or comfortable. Weigh and judge the choices. Cost v return, quality, risk v routine, etc. Look at it from a gestalt super-big perspective: Is it a worthy, timeless, deep, human idea, rich with meaning? If your past burned up, and you could start everything new, would this idea still be bright? Turn the idea around - what is the best angle?
I have an idea but can't seem to start? Say "No!" when you mean not to work. Not "Maybe (probably not)." When you intend to work, yell, "YES!" and head to your work like a comet on collision course. START = ACTUAL WORK (not preparation).
I started. Now I'm stuck. What now? It's important to learn how YOU work. When you're working in the moment, you need to focus on the one part you're working on. But part of you needs to monitor the work as a whole. Then you need to return to work. Eric describes creative work as wrestling with a strange thing from the sea. There's a tension between your original idea and the freedom of the work to go where it needs to go.
[He now has you work on your project for a week before continuing the book. So do it.]