Answers at the beginning of a project usually breed more questions, such as "What causes the large physical foot print of a particular data center?" Is it file servers? Mail servers? Database servers? The answer varies with different data centers. If the answer is file servers, then the question becomes how to best consolidate file servers? Is the answer rack dense servers? Blade serves? Virtual servers?
And the questions and answers keep coming. Basically, keep asking questions until the answers no longer spawn more questions. I know this seems like a seemingly obvious tactic, but you would be surprised by how many people attempt to come up with an answer before asking the question. What role does virtualization play in consolidation? How was it incorporated in your project?
Virtualization does indeed play a very important role in any consolidation project. Unless there is a valid reason for keeping a machine physical -- for example, high I/O requirements, sensitive data- -- it is always virtualized if there is room for it. Projects I have been involved in have virtualized print servers, Microsoft Sharepoint servers, Apple OSX Open Directories, Microsoft ADAM LDAP servers, Microsoft Project servers, Microsoft IIS web servers, Linux Apache web servers, source control servers such as Subversion and CVS, and the list goes on... Can you talk about the tools that a data center manager might need?
One way to handle consolidating many applications is through the use of Microsoft Active Directory. It makes managing dozens, hundreds, and even thousands of desktops and servers a breeze. What can you tell a first-timer project manager that might help him or her avoid a wrong turn?
Shop around. Do not just buy from a vendor because they are your usual source. For example, I love Dell servers. They have been nothing but good to me. However, when looking at blade solutions it is impossible to ignore IBM's BladeCenter and its proven track record. Remember, at some point a consolidation project has to be your first one. Take the opportunity to also examine what else is out there outside the scope of your normal comfort zone. You'll be surprised what you find.
And while this may be your first consolidation project, plenty of other people have done this ahead of you. Look at web sites like SearchServerVirtualization.com and see what plans other people have come up with. There is no need to reinvent the wheel. Unless you have a better wheel idea, and in that case, can I get in on that?