You can't get real sales or business experience from a book. I would say start from the basics in terms of 1-on-1 sales. First, develop a tolerance to rejection; sell something people almost never want like chocolate bars or magazines door-to-door thousands of times. Then, learn to qualify and overcome objections. Without the interpersonal skills of selling, data is worthless and analysis is procrastination. If someone can't hustle, it doesn't matter how great their good or service is because no one will know about it.
Another consideration is to find an equal cofounder who is a superb hustler. Hack + hustle = win.
I personally have sold over $20 million in online marketing and website development services and have a business with 180 full time employees. The parents advice in this post is absolutely correct. The only way to learn to sell is to do it.
You have to sit with hundreds of prospects and learn to listen to what they are saying. To read their nonverbal cues. To respect what they are saying and customize your offerings to match. To leave your ego at the door.
You need to prepare for tons of rejections and even more ghostings. You need to be ready for people to tell you every reason imaginable why you aren't good enough... Then you need to pick yourself up and explain to them clear and politely why you are their best option.
Most importantly, never give up. Just trying over and over again until you are sick of hearing yourself talk is the only way to master sales.
Another consideration is to find an equal cofounder who is a superb hustler. Hack + hustle = win.