This is a list of resources that I recommend to learn more about software development. It is not meant to be complete and I will update it whenever I come across something noteworthy.
Clean Code
Code Complete 2 - Steve McConnell
The Pragmatic Programmer - Andrew Hunt & David Thomas
Professional PHP - Patrick Louys
The Clean Code Talks - Google Tech Talks
Dependency Injection - Programming With Anthony
Security
Cross-site Request Forgery (CSRF)
Prepared Statements - Programming With Anthony
Architecture
Architecture the Lost Years - Robert C. Martin
Domain Driven Design
Domain Driven Design Distilled - Vaughn Vernon