How do contractors close more sales after sending a bid?

Help them know the value of what you’re offering. Remember it’s not the product, it’s you!  You’re bringing your experience and expertise to a service they need. Price should only be a byproduct of your service. At that point they will understand the cost to your proposal. At that point you have two types of people the one that will pay the amount you have requested or the one that one that doesn’t have the money to pay for the quality of service you’re providing. People want to pay the lowest price until they understand the process or get burned by to many low ball companies that they pay 2 times the cost of your bid.