Below are some pointers.
1)Go through the data multiple times and get some idea about the dataset.
2)Interpret the data set into dimensions and measures.
3) Think about any derived dimensions and measures that we can derive from the existing data set.
4)Try to relate measures with dimensions and see which combination might produce good insights about the data set.
5)Try visualizing the measure with the different dimensions and eventually build the Tableau dashboard with the different visualizations.