This is a list of practical tasks that I learn in any language. Each point builds more or less on top of the previous ones.

• write a unittest
• read a configuration file
• parse command line arguments
• pass arguments to different functions
• logging
• write to a database
• run concurrent processes
• monitoring of a server process
• reporting/alerting
• create a GUI
• create a web interface
• create a REST interface
• create an installer/deployable app