Lindsay Hill wrote down an excellent list of network management tips. These tips really help you manage your network better and to troubleshoot faster, and less often in the end.
The only thing I want to add to logging is to use Splunk as your central syslog server and use it to search and analyze your log events.
The other thing I want to add has not so much to do with the network management itself, but with configuration. It will really help you out to standardize your network, topology wise and configuration wise. Making a network design and enforcing that design in your network will add to the network stability and the ease of troubleshooting.
Well done Lindsay.