Fundamentals of system administration

• Know your needs. Write a good scope statement. More often than not, you boss won't know what he wants or even worse, will want some thing without knowing the bad of it (yep, experience talks here).
• Accept your limits. Don't expect to hide them (especially to yourself). You won't (I speak by experience, I followed this path, unfortunately).
• When you have the choice, choose the product with the best mix of size of installed base / technical knowledge / genuine interest. Why? Respectively for:
  • Support
  • Maintenance
  • Motivation
  Experimental is fun for your curiosity and to stay ahead of the curse. But it is not fun for your boss or for your users. Don't forget: your job is to make your users job smoother. They are not your guinea pig; you are their servant. If you don't want to run out of frustration and wish an outlet for your desires (I do), get a pet project for experimenting. Me, I run an gamebook association where I dig further in Google Apps than I can reasonably could at work.
• Diagrams! A picture is worth a thousand word. Especially a synoptic picture. On Mac, try Omnigraffle. Expensive, but impressive.
• Make it simple. It will get complex by itself easily enough.