Begin with the objective
For an enquiry campaign, qualified leads and cost per qualified lead may matter most. For a shop, revenue and margin may be more relevant. An awareness campaign needs different measures. Do not place every available metric on the same level.
Define each metric
Write the calculation, source, date range, and exclusions. If two reports use different attribution rules, they may show different numbers without either being broken. Deduplicate enquiries and distinguish completed actions from attempts.
Build a short dashboard
Include the main outcome, spend, and the few supporting measures needed to explain changes. Segment by campaign, audience, or device when it answers a useful question. A dashboard should point to a decision rather than simply display more numbers.
Review over a meaningful period
Check urgent problems such as broken tracking or unusual spend promptly. Evaluate performance trends with enough observations and time for delayed conversions. Record why you changed a campaign so you can interpret the next result.
Your next step
The best KPI is one that helps you make a better decision.