Azure data lake has two parts. One is for data storing and second is data analytics. You can store terabytes or even exabytes for data. In analytics you can write your codes to extract information from the data to get meaningful insights.
Now how you want to grow or in which field you want to grow. if you are good at U-SQL or writing query languages to extract key-phrases from data, then you can focus on leveraging the U-SQL language for running analytics.