Software development is not only about a number of lines in a source file. Software must add value to the business or it consumers. Without experience and a good team, it is hard to succeed.
One of my favorite topics is the principles and patterns in software development. Without technical principles, you cannot write better code. Also, business value can increase if you understand the difference between a good or bad code. During my career, I have used many popular languages such as C #, Java, PHP, Python etc.
"The hardest thing about software development is choosing an approach to solving a problem ..." - Anonymous Internet user