Minimizing external distractions

This one is simple but absolutely necessary. We should double-check that there are no background processes eating away CPU cycles or consuming vast swathes of memory. Being low on available memory will generally interfere with our testing, as it can cause more cache misses, hard-drive access for virtual memory page-file swapping, and generally slow responsiveness of the application. If our application is suddenly behaving significantly worse than what we expected, double-check the system's task manager (or equivalent) for any CPU/memory/hard disk activity, which might be causing problems.