I'm really impressed with the makefiles provided by devKitPro, which is a toolchain for making homebrew on a handful of video game platforms:

https://github.com/devkitPro/nds-examples

They're very clearly hand made, do just enough to be immensely useful, and are well commented enough to be easy to modify for a Make beginner, just like I was back in the day. I'm sure there are other great examples floating around the 'net, but I cut my teeth on GBA and NDS development, and taught myself make by following in their footsteps.