There's nothing I could add regarding the technical aspects of your project, beyond the excellent advice above.

On the other hand, there may be a few points to draw out concerning career advancement.

Wheterh you are in an organization or consulting, it can be very advatageous if the people for whom you're designing feel confident and comfortable, not just when all ends well, but throughout the whole process. You want your superiors/clients to say "He had it under control the whole time, we were never exposed to risks."

That means using the user-input / planning / sign-off / validation steps mentioned in other posts as, in fact, public banners advertising your project management competence. Get user input by distributing written invitations, with copies to management. Distribute your plan, with copies to management. Confirm the sign-off in writing, with copies to management. Etc. You might even start out by publishing your intended steps so people know what to expect.