I must confess, I got a little, er, assertive regarding guest reviews. Okay, aggressive - but can I add, “in a nice way”?
I am told (and did the math to confirm) that once I go over 200 (I have 3, 4-star) reviews, my 4.98 will go to a 4.99. I know, I know- 
I have 4 to go.
I had gone through a a few weeks in the spring where it seemed every other guest was skipping the review. I feigned blasé as long as I could, then took action:
I now wait 2 days - that’s right, ONLY 2 days before messaging guest on the App. My begging goes something like this:
“Hi Blabla:
I hope your trip back to Germany was blabla. I just left you a great review, and hope you’ll find a moment to review us as well colon ) smile. (I draw the line at the emoticon smile or, worse, “!” )
Thanks again for choosing to stay with us, blabla”
Blabla
That usually does it. If not, I TEXT 3/4 days later (cringe, I know!) something brief, but along the lines of “PULLLLEEEEEASE LIKE ME”
No. Just briefly touching on importance of review for guest & host and thanking them for their time (I bravely do NOT mention 5 stars)
Guests have been really sweet about it - a few admitted to forgetting-and I’ve gotten every single (5-star) review since. Yes, maybe they would have anyway, but…I want those 200 reviews and that 4.99 damnit!