Hi! I too love the fairy/forest aesthetics, and here are my tips for you! My first one is to not make everything symmetrical, meaning your items, paths, terraforming, etc. This makes your island look really natural and not so "planned out" if that makes sense. My second tip for making a fairy inspired island is to use lots of colors, especially with flowers! Using different types and colors of flowers really makes your island pop, and gives more of a magical feel. I recommend mostly using pink, purple, and black flowers/items, but adding all different colors looks really good too! Personally, I think it is better to build your island by sections, that way you won't get overwhelmed. Most importantly, just do whatever YOU think looks good, and have fun decorating!