One of the good skill to have is to analyze the SAP Tables. The core transaction is SE16 and SE16N.
You can download the data to excel sheet and analyze them. SE16 and all the table browsing transaction are very sensitive as they can display information about the company.
All the information in SAP is stored in SAP Tables. Some of the key skills you need to master are the following
Controlling the fields in the table and Enabling and disabling the technical and field level descriptions
Controlling the table display width and Controlling the selection criteria for the data selection
Uploading multiple values in to the table field
Excluding the values in the selection criteria
using operators like greater than less than