The secret to effective sales is to have a

Unique selling proposition (USP)

Explanation:

USP stands for Unique selling proposition, which is defined as the concept of marketing first, proposed as a theory for explaining a pattern in a successful campaigns of advertising.

It defines or means that such kind of campaigns should be made unique or distinctive propositions to the customer or clients in order to convinced them for switching or shifting the brands.

So, the secret for having a effectives sales, to have a USP (Unique Selling Propositions).