I would like to share with you the best practices and conventions for Magento 1 that I've been implementing for the last 7 years.
I will be editing this answer with more and more information, and I would like to hear more about your best practices and conventions.
Based on your participation on this topic, I will edit this post in the topic and I will add your best practices as well, so we can use the first post as a "wiki" and improve it with the collaboration of everyone in the forum.
Agreed post..!!! related to the Magento 1.x best practices and conventions.
Thanks for sharing the detail and make us updated