Assuming you're a developer......Pick a Y Combinator company that has gotten to the point where they are hiring sales people (ie probably 18 months + old) PG has a mantra that you should hire engineers/developers to do a lot (all?) tasks - non engineering ones. I think you'll therefore find companies with a pre-disposed culture to hiring developers into sales roles.

If you do this try and ensure that your boss or at least whomever runs sales overall does have a strong selling background. Like any discipline you'll want a great mentor - especially at your first gig. The recommendation to start as an SE is also a great idea.

Come join Elastic (https://elasticsales.com/) and we'll teach you.

I'd probably start as a sales engineer or maybe as a consultant.

Sales Engineers range from almost "a developer who also talks to customers to get requirements and feedback" to "a submarine salesperson" (i.e. the Palantir Forward Deployed Engineer). If you want to learn sales, obviously pick one where you're in contact with existing salespeople and ideally where you get paid a % of sales on top of salary.

Having a strong technical background does help in selling some b2b products, especially developer products. (or really, "having strong domain knowledge does help in selling a domain-specific b2b product", i.e. being an MD selling medical IT)

It's all about who you know. Go to parties and meetups all of the time, then go to work where all the other talented people work. Rinse & repeat for best results.

Talk with people. It's really just that simple!

I'm stumbling into picking up b2b skills myself. That said, I'm lucky that I have a super technical biz where I'd only allow core engineers to be running the b2b sales convo with customers.