One thing that I seem to come across often enough is the old auto-growth settings from SQL Server. 1MB for data files, 10% for logs. This was a horrible default and is now adjusted to be a bit more reasonable, but even after adjust files I find that some still slip through the cracks. I adjusted an old TSQL script to check for files on the server using the old settings and adjust them to use 500MB for data files and 100MB for logs. This is just a basic script that checks and generates TSQL for the files with those defaults. It can be adjusted pretty quickly to check other things.
I hope to update this with a PowerShell script to do this at some point, but for now just wanted to create something that can be run for a server and help adjust those defaults to something that won’t cause quite as much trouble. Of course, adjust as appropriate for your situation. These aren’t the optimal settings, but should at least be better than the old defaults.