How can I ensure that my code, program, or software is functional and secure?

Ensuring code, programs, and software is functional and secure can be done by laying a good foundation for them. As far as software testing goes, we can do this by testing our code early, and testing it often. Testing our code early ensures that we will not have bugs that are deeply embedded in the roots of the code, which are going to be harder to find later. Testing often is something that we can do to ensure we are really ironing out and perfecting the code along the way, as opposed to trying to do it at the end of development.

How do I interpret user needs and incorporate them into a program?

It is necessary to figure out exactly what it is that the user is going to need in the program, both for functional and non-functional requirements. Once all needs have been documented, following them to the best of your ability is necessary so the customer is satisfied. As long as the foundation is strong, and the user needs are being implemented properly, the user should be satisfied.

How do I approach designing software?

Once again I want to circle back to building a good foundation when designing software. I start by first understanding all of the user requirements, functional and non-functional. Next, I design a plan to understand how this software will work, and how it will flow. I note down the processes and how they work together, as well as a brief outline of the code itself. Once the code has been written, some testing can be done to make sure all input processes are working as they should. Without a plan, actually coding the project becomes a nightmare.