Ask IH: Solo bootstrapped founders, how did you do pre-sales?

I've read a lot of stories where successful solo founders mention the importance of pre-sales (which I agree with).
Founders on here who have done pre-sales: Could you please share your experience? How many tries did it take? How did you reach your prospect? Was it inbound or outbound?

I'm a solo dev building my own SaaS in a space where a few products exist (bootstrapped and funded) with revenues ranging from few hundred thousand to millions. I'm confident of building it on my own (doing this right now). But I'm looking to do a pre-sale and reading about your experience could help!