Well, since there's the dream suite now, you can go lurk in one of it's designated threads on this forum (there's the official one where people put preview pictures etc. and another where they just drop the DA to make it "random") and visit a bunch in one go, taking screenshots and/or writing down ideas and visuals you really like.
From my personal experience, taking a photo of a real-life landscape and trying to replicate that never works out. AC works and looks so vastly different that each and every time it just did not come out looking right. I was also never impressed by other people's attempts at recreating irl sceneries. But maybe that's just me.
What worked out the best for me was literally just going with the flow, creating a general shape of each area first and then looking at the whole picture and deciding if it looks good and cohesive, before jumping into any detailing. To me, having a clear and well-put together image of the entire island is much more important than having a lot of really small thrown together areas that only mildly match each other (and then you'd also run into the trouble of trying to connect all of these areas in a pretty - and most importantly ACCESSIBLE - way. I can NEVER find my way around these over-decorated and landscaped islands)
Last but not least, for areas you could try and do... maybe think about your villagers, or villagers you might want on your island, and think about what THEY'd want. Maybe make little backstories for them, like idk, maybe someone wants to be a beekeeper or something, so you can make them a little bee-area (
I don't know what that's called I'm sorry lol). Think of what you want the structures that are a mandatory part of your island to look like: Do you want your museum to be surrounded by an excavation site? Or would you rather like something more sophisticated? Maybe a place of learning if you're interested in having more than one player house, then you could make like a university for it and decorate it to match. Or you can put a tent near it and try to recreate the tent Blathers used to have before his museum was built. Think about what you want the shops to look like: Highstreet or maybe taken over by nature and nestled into a street corner, like those japanese aesthetic photos you can find everywhere.
Also wanted to mention that sometimes, things you thought worked out GREAT in your head will translate really badly once put into the actual game, as it happened to me quite a few times. But as I tried to recreate the picture floating around in my head, I had a new understanding of what actually COULD work instead, because I was directly terraforming and seeing how everything looked in real time. That then spurned new ideas and I redid the area before even finishing it first. So don't be afraid to drop an idea that you held onto for a while if it turns out to not look so great after all. You gotta be flexible because Nintendo's restrictions are weird lmao
I also really like the idea of having a seasonal area where you switch out the decoration with each season, keeping things fresh and also preventing you from tearing the whole island down again because you have decorating-fever LOL
And that concludes my novel. A long read I'm sorry, but I do hope what I said can be of some use to you
