It's taken a few false starts and experiments for me to become comfortable. Eric Meijer is an excellent resource for understanding the theoretical underpinnings and the 'why' of it all.

Soundcloud has a reasonable and practical approach on Android: https://www.youtube.com/watch?v=R16OHcZJTno

A good bet is to search Github for projects where common Android APIs or libraries are Rx-ified. You'd be surprised at the economy and simplicity of code you can find in some of the best Rx implementations.