Using forced perspective to make small items look bigger is a good way to make small areas feel bigger I think.... That's what I did for my lighthouse.
I have friends whose islands seem massive as they are mostly one level or tiered rather than random cliffs (e.g. north of island is cliff, south of island is flat). Also making a shopping strip and making all your villagers all live in a "neighbourhood" rather than spread out frees up a lot of space.
I’ve clustered my villagers up into groups of 2s and 3s so I have afew larger areas I can mess around with, I feel like making small rivers makes the area look abit bigger. Also chipping away at some of your cliff areas can make it look a lot more open, you don’t need to take off much! But I found that even taking of 1 square around my museum makes the lower ground look a lot larger
I almost leveled all the land on the island, since Ididn't know what to do with cliffs anyway. so I only had only in the north. once I did that, A LOT of land freed up. so much more than I expected.
If you fence everything off and create very rigid paths it could take a very long time to get from one end to the other. That's a guaranteed way to make the island feel bigger than it actually is...as well as making it annoying for anybody apart from awestruck visitors who don't have to live with it on a daily basis.
It's also a balance of items and empty space. Even having a custom design of flowers or stepping stones on every empty space can make an island feel small. I've been on islands where every singled square had something (plants, custom designs, paths, furniture) and it felt so crowded. It's just a pretty island but not very functional.
Different zones help too I think.
When I fill in an area nicely it feels a lot bigger.
For example today I finished my rock garden. The empty space it was in wasn't even that big really. But now its filled in nicely and is themed and such it feels bigger.
Watching videos islands that have areas with different purposes or themes feel larger than random items scattered all over. Might just be me.
My island felt the biggest when it was flat but now I have layers for different things.
I feel like I've noticed you have
1feel bigger because its organized
Or
2 feels bigger because its literally so chaotic everyone gets lost a lot
Something a lot of people aren't saying that makes my island time consuming to traverse is introducing dead ends and areas you can only access via a set path. I've blocked off a lot of my cliffs with rivers and bushes so you can't just ladder down them, and tend to leave my vaulting pole by the airport and only use it on tours. There's also fencing and bushes in many places, so there's areas of the beach you can't just walk onto and have to go round etc. Adds a layer of complexity, as opposed to just running directly at the next place you're going to
On my map I've drawn 2 of my walkways that can't be shortcutted.
Black path is the only way to get from my rock garden and Admirals at the top of town, to the secret beach, is an over a minute long journey via the museum, plaza and several villagers.
Red path is Stellas house, Nooks and the dock. All of which are geographically close but on different cliff heights and blocked off so you have to go via the ramps. And the town dump by the entrance has bushes down the side so you have to go round that too. Either way you're going halfway up or across town, to then walk back.