C++ is widely used in constrained and/or critical applications. How do we manage using a large multi-purpose language in such environments? How can we better use facilities from and techniques from modern C++ (C++11 … C++20)? The best answer is not “use only facilities available in C and C++ in 1985.” This talk focusses on a top-down approach to achieve safety, performance, and maintainability. It touches upon the C++ Core Guidelines, compile-time computation, type deduction, the span and chrono standard libraries, and error handling.