I've been through this exact frustration, read everything there is on the topic, and have discovered things that work and things that don't.
First and foremost - DO NOT go hire anyone to do this for you. No one can. You MUST learn to sell your own products and services, there is no way around it. And no one can do it better than you.
Second, avoid paid advertising before you've learned how to generate high-ticket sales WITHOUT it.
Paid ads and sales people are for scaling only, once you've got your offer and your messaging down to a proven working system.
The good news is, you can get started easily and you can see results quickly, without spending a fortune on anyone or anything.
If you'd like some hand-holding through this, ping me at code+hn@a115.co.uk