The data. I study the data. The database model. The cardinalities, unique keys. Dataflow. If you understand a good chunk of that, other things can fit in around

The data. I study the data. The database model. The cardinalities, unique keys. Dataflow. If you understand a good chunk of that, other things can fit in around it. As for understanding code, deep dives, fix bugs, try to write a feature. After doing a number of these you start to get a picture of some details, characteristics of the programming style, and start making connections at higher levels.