Learn the basics from the official documentation or through a course.
1
If you want to write an Ansible playbook for Nginx, first configure Nginx manually and see how the components and configs work. Then start writing the playbook.
2
Ensure you learn test-driven infrastructure development. There are testing tools for every automation tool.
3
Community modules are a great reference to learning. You can learn complex logic from community modules.
4
When using community modules, ensure you know what each block of code does.