Thorbjoern Mann's book, "Time Management for Architects and Designers" has a lot of good advice that applies to people doing network, system, or software design! No, I don't design physical structures or objects, but it's still design. There's always more than one way to satisfy a goal. And making Design Decisions that harmonize to create a good system or network overall is important.
He makes a great point about Pet Ideas. A "pet idea" is a way of solving a problem, or designing the system, and you have an emotional commitment to it. The danger is that you won't examine other options, because you'll be defending your pet.
For example, suppose you're designing a system to manage IP Phones. These devices -- like the Polycom SoundPoint IP SIP phones, Cisco, or Aastra phones -- all download their software and configuration from server, usually using FTP. These phones are Customer Premise Equipment, CPE, so we call it a "CPE Management" server, or "CPEM" server.
Suppose you need to separate one group of phones from another; for example, some phones belong to a legacy platform, but some belong to a newer platform. Normally, all the phone configurations and software are grouped together in one place, but you need to separate them. The first idea that comes to mind is to build a new CPEM server, then have all the new-platform phones talk to the new server.
This can easily become a pet idea; you might feel the need to defend it, and to point out deficiencies in alternatives. The danger is that another idea -- say, establishing a new FTP login and new file directory for the new phones -- might be much easier. But if you're committed to the first idea, you might not really consider any other ideas.
I get automatically attached to the first idea I have. But this really isn't healthy, because I spend too much time considering the advantages of that idea. I really need to consider both advantages and limitations for this idea -- and others too.
Dr. Mann recommends that you come up with at least two ideas, so that you have something to consider.
On the CPEM server, I've already mentioned a second idea. Here's a third: instead of a different server, or a different login, you a different file transfer protocol. Simply retain the use of FTP on the old phones, and HTTP on the new phones. This means you can keep the same login credentials, but use a different service on the server, and therefore a new directory.