The only sales book I really liked was How You Make the Sale by Frank McNair https://www.amazon.com/How-Make-Sale-Frank-McNair/dp/1402204...

A lot of sales books teach Jedi mind tricks and "tricks to close" and crap like that. This is much more practical. It walks you through a customer's buying process and shows how you can map that to your sales process. I find that making a better connection with my clients comes from putting their best interest first and being a good person. No need for psychology or tricks. Once you understand the buying process, and you understand the products/services you're selling, you're good to go.

My favorite is How You Make The Sale by Frank McNair https://www.amazon.com/How-Make-Sale-Frank-McNair/dp/1402204...

I came from a technical background as well and this was the only book that really explained the process to me without a bunch of "closing tricks" or other gimmicky sales tactics.