What is a good process for developing a new course from scratch?
I strongly recommend backwards design as a way to plan and build a course. The key idea is to start out by clearly laying out for yourself what results (skills, concepts) students in the course should end up with, then figuring out the assessments that will assess this, and then course activities, assignments, etc., that will feed into this. This works very well, in contrast to the "standard" approach of focusing first on content -- making a bunch of readings, slides, etc. -- and then asking later what sort of tests one can make, which invariably leads to the realization that the assessment gets at peculiarities of that particular content rather than the goals you really wanted. With backwards design, things make much more sense. There are a lot of good references on backwards design (just google it), e.g. this.