Superconducting qubits have provided a strong path towards viable quantum computation. As qubit systems scale up in size and complexity, the performance of single qubits and multi-qubit logical operations become an important limiting factor. While a great deal of progress has been made, the existing superconducting qubit technology still faces several hurdles and limitations. There remains room to improve and understand the limitations of coherence in different types of superconducting qubits, as well as in two-qubit gate fidelities and efficient qubit readout. This thesis will explore the time-dependent fluctuations of qubit coherence times, including non-Markovian effects, and discuss the implications for future device performance. In addition, I use two-qubit randomized benchmarking to characterize a two-qubit fluxonium gate with 99.49% fidelity, which is a promising tool for a future quantum processor. Finally, I will use readout fidelity measurements to characterize a first-of-its-kind cryogenic integrated circuit capable of doing qubit readout with 99% fidelity and show that this can replace much of the standard readout architecture.