I will sent a message to the guest (only to the someone I will recommend to other hosts ) after a day they checked out, to remind they give me a review. These friendly guests will have a higher chance to write reviews to you, especially when the evaluation interface is very complicated and multi-page now.
For example,
Hi [Guest name],
Thank you for being a responsible guest. The next time you visit [you city], we hope you will consider us again. We will be giving you a five star review.
When you have time, please leave me a review and any private feedback they have to offer so I can make things even better. Airbnb hosts are very dependent on our guest's reviews, and I'd greatly appreciate it".
Thanks again,
[Your name]
Please pay attention to two points when you send a message,
1) Pay attention to the time difference. You will never be happy if receive the message in the middle of the night.
2) I don't recommend you to send the message to terrible guest. If they don't respect your house, you can't expect them will give you a respectful review.