Brain-computer interfaces (BCIs) aim to establish direct communication between the human central nervous system and computers, bypassing the need for muscular engagement. This technology holds immense promise for a wide range of applications and has therefore attracted significant research efforts over the past few decades. This chapter provides a comprehensive introduction to the underlying principles of non-invasive BCI development and presents an overview of state-of-the-art BCI solutions. Additionally, it addresses key considerations pertaining to data acquisition, user experience, and ethics, highlighting the current challenges in these areas. Furthermore, based on the latest research findings, this chapter suggests guidelines for future BCI development, paving the way for advancements in this field