When I work on a design project, my work process is the following. I start by asking the client his/her general idea he/she wants, I brainstorm those ideas provided and I make some sketches.
I send these sketches to the client to know his/her comments and comments about it and then I proceed working on the piece considering the feedback.
The client will be kept continuously informed about the illustration progress, which will also be shown to take into account the client’s feedback about it and make any changes considered necessary on the illustration, if any.
Lastly, for the completion of the design, depends of many factors, like the complexity of the image, requested changes, turnaround time, among others. However, an estimation can be provided once the basics of the work to be done are discussed and clear