I've written my first tip for MSSQLTips.com:
How to setup and use a SQL Server alias
It's a pretty simple thing to do, but it can be extremely handy in a recovery situation. For our disaster recovery tests, we configure the aliases on the application servers such that their configuration settings don't have to be changed. As a result, what they think is "MySQLServer" may really be "MyDRSQLServer" but the OS handles the connection through the alias.