We're living at the era of video tutorials. You can find a Youtube video containing anything you need, in detail, for your development. While they contain good information, but they're not immune to changes in code reference and also may not tell you the best way.
As you know, WordPress is open source and it changes all the time. If you write a code today, in a month, it might not be the best way and other approaches may appear in the community.
You should remember that you can find the best way to do somthing in WordPress, in developer reference.
I talked in deatial about the developer reference and how you can get the best out of it in this video.
In WordPress Developer Reference website, you can find the information about four main sections:
In each section and each page, there is information about how you can use the function or class.
You can see that what parameters with which type of data this function accepts. You can see that what kind of data it returns.
Also you can see the source code of the function in the WordPress trac.
User Contributed Notes
A useful part of the reference is where users contriburted to the documentations. This contribution can be writing good code examples, tipping about a common bug or explaining the missed things in the reference.
As a WordPress developer, you can contribute to writing code in the reference too. You only need your WordPress account, some development knowledge and a good problem to solve.
How did you learned to code? Do you prefer video tutorials or just plain code? Do you read a whole programming book or just read the sections you need?