There is no better way to learn electronics than building your own gadgets. This guide from Carl Gordon Media shows how you can use a Raspberry Pi 3 and a few other parts to build your own smart mirror. The project took about $100 to complete.
The Smart Mirror Pi can display the weather, time, date, and other useful information. You will need a reflective window film, picture frame with glass, desktop monitor, HDMI to VGA adapter, and a few other parts to complete this project. More information is available here.