The first and foremost step to building secure Android app development in Lahore is to follow secure coding practices. This includes using secure coding techniques such as input validation, output encoding, and secure storage of sensitive information. It is also important to ensure that the app is developed using a secure development framework and programming language that can help detect and prevent common security vulnerabilities such as SQL injection, Cross-Site Scripting (XSS), and Cross-Site Request Forgery (CSRF).