I came up with what I think is my best idea to date. I'm stalling on building it out the product because to be honest, I don't know if I can do sales. To be clear, my product is B2B, specifically local businesses.
A lot of advice in this area should probably start with "it depends, but..." so take this with a grain of salt.
If you have the interest, drive, and time to build it (and especially if it's your best idea), build it. Try to build exactly enough to convey your vision, without spending unnecessary time (that's hard, though!). Think about sales, but don't worry about sales yet.
While you're building, post details and lots of updates here, on Twitter, and hopefully in communities that cater to your audience. It doesn't have to be super personal... the facts should be interesting to other entrepreneurs.
By the time you're done building, you'll either have some following or you'll realize something's not landing with your product. If you do have a following, a question exactly like this one- but with invested followers and a product to show- should get you some specific ideas and possibly even a partner to help you sell.
People often suggest partnering as a way for introverts to sell... but it's just as hard to find a partner when you're introverted! That's why a good, functioning product is important... it's the necessary credibility to bridge the introvert gap!
What do you think is holding you back from doing sales right now?