Gus over at PiMyLifeUp has done a great tutorial on using the “famous” MCP3008 analog-to-digital converter chip to read values from a light-dependent resistor. He goes through wiring it up and programming it using the spidev Python library. I prefer the GPIO Zero way of doing things now, but Gus’ way teaches you a little more about getting the values out. He also goes through setting up the MCP3008 inside MyDevices Cayenne, a great IoT platform. Read how Gus does it here.
If you want to get into analog sensors, and don’t want to bother with all that wiring (!), keep an eye out for a Kickstarter coming soon featuring Alex Eames’ Analog Zero board.