Use call tracking numbers that swap dynamically by traffic source, and log the outcome of each call in your CRM. Without this, phone enquiries appear as unattributed, which systematically under-credits whichever channels drive calls.
Keep the number format and NAP consistent everywhere for local search.
Record call outcome, not just call volume — a tracked call that went nowhere is not a lead.
For low volume, simply asking 'how did you find us' and logging it works well enough.