Most Indie Hackers aren't the biggest fans of selling or grinding out customer development.
I believe part of that is you have to spend a lot of time figuring out who to talk to, getting rejected, going in the wrong direction, what are the right titles, where are the opportunities at an organization, what is the buying processes, what messaging works, how long are the sales cycles, what are the common objections etc. Figuring out who your ICP is time consuming and requires a lot of experimenting. Plus there are a lot of things you don't know, you don't know.
Basically, there's a lot of info collecting and experimenting you have to do early on that isn't talked about much as you navigate the B2B landscape trying to sell your product and learn about the industry from a sales and marketing perspective.
So what's the hack? Find salespeople on LinkedIn who sold into the same space previously and talk to them. Tell them you're not selling anything and you believe they have the experience that can help you cut through the fog. Most salespeople are very helpful, especially if you're a tech founder.
They will tell you everything they've learned. They will tell you the right types of companies to target or avoid. They will tell you deal sizes, sales cycle length, what messaging resonated, what didn't, what are the pains or problems prospects are solving. They will tell you if you cold emailing works or if cold calls are how they booked most of their meetings. Or if their buyer is impossible to reach from cold outbound and you'll know you need to ramp up marketing.
They will tell what prospects couldn't care less about. They will tell you what products they lose to and why. You can gather so much intelligence so easily. And you will accelerate your learning process. It will make your life so much easier. I could write manuals about selling into specific spaces that would improve the chances of someone's GTM strategy by a ton.
I recently did this for a startup I'm working on and this person told me about categories I never considered targeting, told me which companies we were too early for and why, why some companies we might target might seem like a good fit but are a trap (side note: you may think your product is a good fit for X but the real reason is a,b,c, and they've already tried targeting X and can explain why it's not), where there are overlooked opportunities, the types of clients to avoid, what the common objections were, from a product and operational standpoint we learned the features that resonated and the ones nobody cared about (even though they thought they'd be good, operationally what problems they ran into and why clients churned.
Hope this helps!