@Angela221 You can always message the guest if you feel like it, asking if there was anything you could have improved upon in order for them to give you a 5* Overall rating.
But you should understand that Airbnb tells guests a 4* rating means that the place was Good. So they may not have any complaints at all and think they are giving you a good review. It's Airbnb's faulty rating system and ridiculous rating system for hosts that is at fault, not guests who give 4* ratings.
About the only thing you can do to counteract this is to let your guests know how hosts are affected by the ratings. If you have interaction with your guests during their stay, you can find a way to mention this, if you don't see much of your guests, you can leave an explanation of star ratings in the house manual.
I host in my home, so I have quite a bit of interaction with my guests- conversations over coffee in the morning, or sharing a glass of wine in the evening. When I get around to educating them a bit on how Airbnb penalizes hosts for anything less than a 5* rating, they are shocked. One guest said she felt terrible, because she'd rated the previous two places she stayed 4*s, thinking that was a good rating- she had no complaints about the place or the host and said she'd stay there again.
I would never tell a guest to leave me a 5* rating, I just let them know how it works from the host's end. Once they know, nice guests who enjoyed their stay will be likely to rate you 5*s.
