Source: MMOWTS
In ACNH, once you unlock the terraforming and start improving your island, then you can focus on getting a 5-star island ranking.
Isabelle in Resident Services will rate your island and provide some suggestions for improving the island. She may tell you that your town needs more decoration, or your town needs fewer trees. MMOWTS has a rough estimate number of reaching a perfect island. Below is a list of islands that have received a 5-star rating.
* Around 20 Nook Miles furnishings (purchased with Nook Miles from the Nook Stop)
* Around 50 DIY furnishings (crafted yourself or by friends)
* Around 40 store-bought furnishings (from Nook’s Cranny or Nook Shopping)
* Around 50 fence segments
* Around 110 trees and 10 bamboo thickets
* Around 250 flowers must be bloomed, not sprouting or budding
* 7 bridges
* 6 ramps
In addition, it is also important to maintain communication with Isabelle, to ensure that you are going in the right direction. If she stops telling you that you need more furnishings, you can move on to the next goal she mentioned. Your rating will be updated immediately to meet the next requirement, so you don't have to wait until the next day.
To avoid waiting for the flowers to bloom or the trees to grow, you can use Nook Miles Tickets to travel to the Mystery Island and bring some fully-grown plants back. A few dozen flowers in a trip may fill your inventory.
This can make your island more popular, and 2.0 Update brings a lot of new content, you can also use ACNH 2.0 Items to decorate your island, this will be a new level.
Because Nintendo has stated that the 2.0 Update is the last major update of ACNH, many players will not want to miss this rich new content, and MMOWTS will provide all the help you need.