Here are some tips from my point of view as a project manager. I originally put these down as reminders for other PMs out there, but I think they shed light in general on our collaborative site-building process. There's no order of importance here.
Building a complex marketing website is a big job and will require the team's input and executive sign-off on a number of benchmarks during prototyping and design creation. A "too many cooks" problem could be clear from the outset, but a project can be slowed down by a gradual decentralization of communications, so as a project manager I try to...
1) Establish and maintain one point of contact.
Clearly, one point of contact can't always happen, depending on the client-team's organization, how responsibility is delegated and how agency partnerships are handled. But my most successful projects have had a single person on the other side, mirroring my role within my team. With a three-way agency/client/developer relationship, having a single main contact for each helps communication in general, as well as email consolidation and documentation of key decisions. It's important to avoid a scenario where requests come in piecemeal from several people.
2) When in doubt, pick up the phone.
We all receive dozens of emails daily, but a call can stand out and be quicker than you think, so I like to remind myself to communicate by phone more than I probably think is necessary. Email does so much — documents, provides searchable reminders later, sends to a group at once — there are many reasons to rely on it. But it's no news that the subtleties of verbal communication can be lost in email, and a call is just more comforting. Having one p.o.c. (#1) makes it somewhat easier to use the phone regularly. Unfortunately, it's still usually important to send the "are you available between 2 and 3:30 today" email, as well as the post-call documentation/followup email, but regular calls will pay off for the relationship in a big way.
3) Consolidate! Consolidate! Consolidate!
It's extremely helpful if communications come in one compiled email rather than many single-topic messages. It's tempting for both clients and me to send questions or decisions one by one as they're conceived, and to settle into a back-and-forth mass of emails, each with one or two issues. If the topics start to bleed between these multiple communications, it can be really hard to keep track after a while. So, it's good to encourage everyone to compile communications. Especially in a content entry/QA phase, it can be really hard not to have some request slip through the cracks if you are getting requests and questions sent one by one. As project manager, you will spend precious time compiling these incoming requests for your development team, whether you use management software or not. By asking all players to simply compile tweaky requests into an email, it helps everyone organize and keep track, as well — it's not asking clients to do your work for you.
4) Be early to the meeting.
Try not to procrastinate communicating changes to schedule or scope. Maybe "procrastinate" isn't the right word. Even if experience tells you that schedule or scope will be affected by a development, it's tempting to wait just a bit and see how this suspicion really shakes out once quoting and resourcing questions are considered. But just by mentioning that a schedule could possibly be affected before it's certain, a project manger can remind everyone that we're working with a team that has a larger production schedule. Keeping considerations of schedule in the air, so to speak, now and then, we can avoid delivering a shock if a problematic change is requested during the site build.
5) Canned responses help you help them.
This might be obvious. It's something that requires updating but can ultimately be a good way to save time when keeping a team informed. Develop a bank of starter emails for key communication points shared by typical projects. These aren't quite templates, but most projects will share key points that require certain communications (for me, some of these are the kickoff/schedule explanation, meta-data/301 redirect explanation, DNS explanation/DNS contact reach out, etc.). If you have enough of these email starters developed, they can also work as a sort of project anatomy--reminders for you as new phases approach--and once customized and sent, they can really save time documenting in writing the important reminders you are already telling clients during meetings. There are are also some set docs that we send for most projects, and many educational blogposts and newsletters on the Newfangled site to support projects in process.
What else do I need to know?
As a PM, I've learned a ton over the past 5 years or so about how to do my job managing web projects better, and I've seen the results. But I'm still learning. I'd love to hear from you about what you think I should know, so that I can do an even better job anticipating the needs of the people I'm working with.