The software development lifecycle (SDLC) consists of several key characteristics, including planning, design, development, testing, deployment, and maintenance. Each phase is crucial for ensuring the delivery of high-quality software that meets user needs. The process emphasizes structured documentation and clear communication among team members, which helps manage project scope and timelines. Agile and waterfall are two prominent methodologies that guide the SDLC, allowing teams to adapt to changes and deliver iterative improvements, ultimately leading to successful software products.