The tunable transmon is an attractive platform for utility-scale quantum computing. However, this approach requires exquisite control over both the baseband pulse waveforms and the low-frequency flux noise environment of the qubits. I describe improved characterization of the frequency-dependent transfer function of the qubit flux lines, and I demonstrate accurate qubit control by appropriate pulse predistortion. In addition, I describe the fast, versatile characterization of the qubit noise environment and show that the measured classical noise is predictive of qubit phase coherence. Finally, the ultimate gate performance is set by intrinsic qubit noise. I describe progress in understanding and suppressing intrinsic low-frequency 1/f flux noise.