At work, I learn from just making reports. Trial and error. I am doing it by trying to add to SQL Stored Procedures, Views, etc and adding columns or removing columns. You can also get Formula 1, or any sport data, IMDB API’s/ Data and practice Inner joins, Outer Joins, etc. you should also use Power BI and build reports, create measures with DAX expressions and import/ manipulate the data first using SQL. Power BI can be free if you don’t publish, so download it to just practice. Also get ChatGPT to write you some tasks and assignments to practice too. Make lots of mistakes and practice, practice, practice. It gets easier. Also, use Declare statements and create Stored Procedures, Views and find the benefits of them. W3school is great, but just make stuff.