Typically the common compliant when someone’s stating they need to tune a SQL Server is that it’s running slow. What does slow mean? Is it a certain report, a specific application, or everything? Did it just start happening, or has it been getting worse over time? I start by asking the usual triage questions of what the memory, CPU, and disk utilization is compared to when things are normal, did the problem just start happening, and what recently changed. Unless the client is capturing a baseline, they don’t have metrics to compare against to know if current stats are abnormal.
Tuning is about method and tools (in that order). I like the way Tim does both.