In this section I want to give out some good Resources to get more info about Power BI and Tableau. This will hopefully help you in your Business Intelligence Journey.
These are the resources that I would have liked to know about when I first began to learn Power BI and Tableau. Everything from Youtube videos, Books or different ways to be able to practice your knowledge in different practical aspects with good datasets.
I would say that Marco Russo and Alberto Ferrari at SQLBI is the best resource for learning Power BI. They have written several books such as "The Definitive Guide to DAX" and "DAX Patterns". They also have a homepage and a youtube page with a lot of really good Power BI content and DAX Content especially.
My final of my top 3 resources for Power BI must be Guy in a Cube. Their Youtube Page have tons of information about difference concepts of Power BI, especially regarding more advanced concepts. I do especially like their weekly recap of what have happened in the Power BI sphere on social media and their weekly "Power BI Tips from the Pros".
Andy Kriebel is the person I have learned the most from regarding Tableau. He got a great youtube channel as well as his blog VizWiz. On his youtube channel you can find information about how to make a lot of different visualizations. As he is the founder of MakeOverMonday he also post his "Watch me Viz" on his youtube channel which are great.
If you only can chose one person to follow regarding Tableau I would definitely recommend Andy Kriebel.
Okay, this is not really a Tableau resource. The reason for why I include it here is because I think this is the best visualization resource there are out there. Cole Nussbaumer Knaflic has a home page storytellingwithdata where she post visualization challenges each week.
Besides this she has an amazing pod cast where she really go into deep into how to create a data driven organization. She has also written two really good books about how to become better at storytelling with data
As the two resources above gave you a great way to practice your tableau skills as well as some theory with books, Udemy offers several courses that I think really explained the in-depth of Tableau in a good way.
I used this and this course when I studied Tableau to pass my two certification. I think both went through all the basic concepts in a good way that I could understand. This could be a good complement to the practical approach of the other resources.