Idea to first customer: what do you actually use?

Hey everyone! What's your stack for going from idea to something live? What's the hardest part; the building or finding customers? What do you guys do to get your first customers? Have you tried scaling something and getting past $500-$1,000 MRR?

I'm building something in this area but not trying to sell anything. I'd just love to hear your experience and if you're up for a quick call, that'd be amazing!