In my opinion to learn Tableau effectively the some basic and very important steps are: Good Understanding of Statistics. Well versed with Database Concepts. Good Understanding of Data Modeling. Ask question from the data sets. Visualize the data to put it in different types of graphs/charts etc.What is tableau used for?
Tableau is a Business Intelligence Tool used for data visualization. With Tableau you can gain insights by just visualizing the stats that you already have with you and use it for your development of your business.