You don't want developers to follow a checklist, you want them to use their intelligence.
One hour is enough to make developers realize they know nothing about cryptography. Once they reach that point, they will be on the right path (ie really learn about the topic or ask someone who knows).
The most common error isn't improperly used algorithms or techniques, it's improperly used cryptography.
Example: securing a file with AES-CTR and having the password hardcoded in the binary.