What framework helps prioritize initial GTM channels and first 100 customers?

[John14]

My co-founder and I have built a solid B2B SaaS product for small retail businesses, but we're now stuck on crafting our go-to-market strategy for startups. We have limited runway, so we need to be extremely focused, but we're debating whether to start with a broad content marketing approach or a highly targeted outbound sales campaign to a specific niche. For founders who have successfully launched, what was your framework for prioritizing your initial channels and defining your first 100 customers? How did you validate your pricing and messaging quickly without spending months building a perfect sales funnel, and what key metrics did you track in the first six months to know if your GTM motion was working?