Aaron is a Staff Database Reliability Engineer at Stack Overflow. We don't want to say he's old, but his experience dates back to a time when SQL Server 6.5 was considered "modern." He writes here at sqlperformance.com, over at sqlblog.org, and at MSSQLTips.
Aaron Bertrand provides more background on the evolution of ParamParser, a PowerShell module that helps parse parameters from stored procedures and functions.
There is a very common anti-pattern you should avoid, involving updating a row if it exists and inserting it if it doesn't. See how to avoid race conditions and deadlocks.
Altering a fixed-width column on a large table can often mean either a lot of planning or a lot of downtime, but in some scenarios there may be an easy out.