I'm a web developer who is part of a three-man team that has been tasked with a rather large and complex development project. Other than some direction and impetus from management, we're pretty much on our own to develop the new website. None of us have any project management experience nor do my two coworkers seem like they would be interested in taking on that role, so I feel like it's up to me to implement some kind of structure to the development process in order to avoid issues down the road.

What can I do as a developer without project management experience to ensure that our project gets developed successfully and avoid the pitfalls of developing a project without a plan?