I learned my way around Renpy modding the original Lab Rats (not Lab Rats 2). Looking through the code of a game you like can be an interesting way to get a basic handle on how things work.
You may need to extract the game code, though.
Unren.bat can help you with that. Once you've extracted the game (if the game files aren't already in .rpy, just in .rpa and .rpyc) you can look over a few things.
The 'starter' story that comes with Renpy can give you a basic idea r.e. how dialogue works as well.
The Renpy cookbooks and the Lemmasoft forums are also good places to look for coding ideas, but sometimes people will talk over your head if you aren't familiar with how things work. People around here are a bit more friendly in that regard, and I've found them to be a bit more helpful on a few things.
Anyways, lots of good suggestions!