This work presents Schema-Guided Reasoning, a method that structures LLM reasoning with predefined schemas enforced by structured outputs and constrained decoding. We describe schema specification and enforcement and the orchestration patterns Cascade, Routing, and Cycle for sequential, branching, and iterative workflows; the method improves reproducibility, accuracy, and auditability, with trade-offs in flexibility and schema design overhead. We demonstrate automated text-to-SQL generation, where SGR reduces critical errors and enables stepwise validation.