Not only is every rule that successful sales executives have learned in large companies not applicable to startups, it is positively detrimental.
When you are validating your idea, you are not going to hire and staff a sales team. You are not going to be executing a sales plan, and you are definitely not going to be executing your “sales strategy.”
The reality is that you simply do not know enough to do any of these things. You may have your hypotheses about who will buy, why they will buy, and at what price they will buy, but until you validate those hypotheses, that is all they are, educated guesses.