I have to admit, original writing projects are my favorite kind of assignment. I feel that they offer tremendous opportunities for personalization and agency, and they also allow for a more authentic perspective of a concept.
My general preference for beginning these types of projects is to provide a model, preferably one created by a learner who is not currently participating in the learning environment. I try to pick something thought provoking or otherwise stimulating in order to facilitate discussion, reflection and personal context.
Having done this, I am ready to provide instructions for the actual project assignment. This is now neatly contextualized within the example and conversation we have just completed. This allows learners to move easily and with few operational questions into the creation of a project draft of some sort (the scope of the draft depends on the project).
I always try to design the draft phase to include ample feedback, both from peers and the facilitator (me or a co-facilitator). With this feedback and reflection, learners are ready to move on to the final version of the project. Again, my preference is for this to be aggregated and shared for discussion.