Three easy tricks to improve the Quality Score of your vacation rental:
 

1. Add 1 or 2 pictures to the properties that are in the limit.

 
If you have a property with 14 pictures you can increase its quality score significantly by adding one or two pictures more. Also If you have a property with 19 pictures,  you could achieve a perfect score by adding one or two pictures more.
 

2. Add some sentences to your description if under 200 words.

 
If you have a property with a description between 189-199, you can increase the quality score of the description by adding one or two sentences.
 

3. Remove pictures with low resolution

 
For example if you have 15 pictures on a property listing, but 3 of the pictures have extremely low resolution, they will drag the quality score of the property down. Try to remove these pictures and preferably add new ones with higher resolution.