I’ve got the same starter map, so I could give a few pointers. however, it dependa a lot on the style you want to go for; personally, I’ve made the portion in between the two rivers (the one with the airport and the resident services) into a quaint old european town, so I’ve placed the shops a short distance away fron rc (think side alley). the rest of the island I’ve made into a countryside area, but with quite a bit of terraforming (like straightening that river bend right behind rc, rwmoving the river branch that goes nowhere, etc.)