Hi,
I recommend MS KB article Q262068 as a starting point.
We used a Unix based email system prior to Exchange.
When I set up Exchange, I did so in a test network and worked with it for about 5-6 months, setting up users, public folders, policies, resources, addressing and address lists, multiple child domains, and such. I also used several reference books: Exchange 2000 Server Administrators Bible, Exchange 2000 Server Admin companion by MS, MS Exchange 2000 Server implementation and administration by MS.
By and far, Exchange server is huge (both in scope and resources) and requires more hands on administration than the old email system we came from. The level of integration between Exchange and Active Directory requires any Exchange admin have a good grasp of Active Directory.
Exchange can be touchy and system changes should be made with care and tested in a test network before implementing in the live environment.
I have implemented a change log, where every proposed change is first written, and then approved by senior management. The change log indicates what is to be changed, when the change will take place, what the benefit is, what the backout plan is, and what the risk of implementing the change is.
Here are some thoughts for you, based on my experience with implementing Exchange, and I hope they help some small measure.
Wyz