Hi there,
Is the review score how many new clients take the time to leave a review, or is my 40% and average of how I'm reviewed which would be a totally failing grade if this was school!
First off, only you (and Rover) see that number. If you click on the little question mark above it, you will see what it means: "Recent first-time bookings reviewed"
Rover will send requests to customers to complete reviews, so I wouldn't hound them too much. Just one or two follow-ups emphasizing how much you enjoyed caring for their pet and that it would be great if they formally completed the review. Not much else you can do.
To add to what Karen said, your scores will change quite frequently. I do recommend doing your own advertising/promotion. If you have business cards go to pet friendly apts, hotels, vet clinics, groomers, independently owned pet stores, etc. close to you and ask to leave some cards. If you can pick up, at least 1 new customer a month that will help. If all went well and your customer was very happy, tell them they will get a request from rover to review the stay or services you offer. If they book with you again that will help your repeat score. Other than that, it is best to ignore the scores if they upset you. Ask yourself how "you" feel you are doing and are your customers satisfied. For me, that is the end result. That said, I do ask my repeat customers once or twice a year after a stay to give me a review.