What was the best thing you did to handle scale?

One if my top concerns is about scale and resource management. Every day we are checking our system to make sure it is live... making sure our system can handle the load... setting team priorities to handle what is most is important... also, compartmentalizing myself to be productive. What is the best thing that you did to handle the various types of scale (Personal resource management,Team resource management, or devOps infrastructure management) ?