Reply with three things:
1. The vertical you're considering (HVAC / dental / salon / etc.)
2. Your weekly time available for sales calls
3. Whether you have any existing local-business connections
I'll give you a real answer, not a polite one. Pick the wrong vertical and you'll burn 90 days. Pick the right one and you have a 7-figure-per-year agency in 18 months. Worth getting the first call right.
James