As a small outfit, you probably don't want to actually sell. The approach that worked for me was to focus on inbound marketing and let customers self-select and come to you. Have a great pitch, ideally right there on your web site. Then get them onto a trial, treat them as customer from day one and get them into your customer success programme.
In essence: build a great product, talk about it, find the right customers and couple with fanatical customer success.
Also, choose a problem for which there is a good audience: https://longform.asmartbear.com/problem/
Generally the literature you're looking for depends on what account sizes you have, as others have mentioned. Advice for selling single $10/month accounts is much different from advice for selling 6-figure enterprise deals.
Most indie hackers rely on social media and SEO for traction. It's more of marketing and less of sales.
Selling is hard. Selling is painful because rejection is painful and rejection is most of selling. Everything is easier than selling.
Looking for shortcuts, tips, and tricks is easier than selling. It feels like work, but it is not. It is just pretending and avoiding pain.
In business, selling is all that matters. Technical competence without sales equals a failing business. Selling without technical competence is a road to riches.
You can hire technical talent better than you. Build the cost into your price and mark it up for overhead and profit.
You can’t hire sales who care as much as you.
Just grinding away at sales is the simplest thing that might work. The only thing better is luck.
Good luck.