Close rate is the share of estimates that become work. It moves on four things, and price is only one.
Speed of response
The estimate that arrives first is disproportionately likely to win, and the effect is largest on urgent work where the customer stops looking once someone answers.
This is usually the cheapest improvement available, because it requires no change to price, scope or presentation.
What the estimate contains
A single number invites comparison on that number alone. An estimate that sets out what is included, what is excluded, and what happens if something is found once work starts, is harder to compare against a cheaper line and easier to accept.
The difference between a figure that may move and one that is committed is covered in estimate versus quote.
Follow-up
A large share of estimates are never declined. They simply go quiet, and are counted as losses without anyone having said no.
This is the most commonly neglected part of the funnel. See estimate decline rate for the distinction between a refusal and a silence, and the estimate funnel for where estimates stall.
Declining work that was never going to close
A close rate can be raised by estimating less. Work outside the service area, work at a budget the business cannot meet, and customers shopping purely on price consume estimating time and depress the rate.
The rate can be too high
Winning nearly everything is a signal about price rather than about selling, and the response is raising prices rather than further improvement here.