Another thing is that when you follow up with customers, don't rush to sell your products. First, let him feel that you know your products and industries very well. If he is confused in this respect, he can find you to solve it. If he asks a question and you can't answer it, will he still trust you to buy your product? Follow-up records and the like should be sorted out, and it is best to use software such as writing to manage customer information and follow-up records.