How to Write a Program/Enhancing code

Usually create variables that will represent certain data types that you want to represent or simulate in your program in comparison to the particular problem needing to be solved or real world simulation-i.e. the basis for your program

Then create or use function/methods that you want your program to perform in order to achieve a specific tasks or real world simulation.

This is usually done in block methods or modules, in which you encapsulate or wrap all necessary data (representations) and methods (and arguments/parameters) into an object / class, which best simulates the basis of what the program is supposed to represent...this is turn is called generating code.

Continuous improvement
Many developers recommend always keeping the code in a state that is ready to build and release to customers at any time. Some projects have a nightly build, while other people recommend checking in a ready-to-build coherent group of edits every 20 minutes.