Requirement engineering plays a pivotal role in the development of complex systems, ensuring that stakeholder needs are effectively captured and translated into system specifications. However, the inherent complexity of modern systems presents unique challenges that can impede the requirements engineering process. This journal article explores the key challenges encountered in requirements engineering for complex systems and proposes strategies for success. The challenges include managing the intricacies of system interactions, dealing with uncertainty and ambiguity in requirements elicitation, addressing evolving requirements, ensuring stakeholder alignment, and accommodating non-functional requirements. To overcome these challenges, various strategies are discussed, including the adoption of agile and iterative approaches, the utilization of model-based requirements engineering techniques, effective stakeholder engagement strategies, leveraging tools and technologies for requirements management, and incorporating risk management practices. Case studies from diverse domains such as aerospace, healthcare, and automotive systems provide practical insights into the application of these strategies in real-world scenarios. Additionally, the article highlights future directions and emerging trends in requirements engineering, including the integration of artificial intelligence and machine learning, advancements in requirements visualization and communication, and considerations for ethical and regulatory aspects. By addressing the challenges and implementing effective strategies, practitioners can navigate the complexities of requirements engineering in complex systems and ensure the success of system development projects.