Thanks, Lokesh. It is my pleasure.
Selling is a very broad subject. There is no one resource that covers it all. And if you truly want to learn, you have to practice the knowledge you gain immediately.
You can start with the book: How to win friends and influence people by Dale Carnegie. Then, let your interest guide you into the specific area of selling you want to master. Find out the best person in that area and consume all their content.