Maybe you can try visiting a bunch of towns/dream towns to get a feel for what kind of layout you like? Maybe you can ask for a bunch of dream codes to WIP/undeveloped towns so the layout is more obvious than looking at a fully developed town?
I personally like maps with a toooon of space and a little peninsula that I can turn into a neighborhood for all my villagers. I buy/sell turnips a lot and so I like Retail to be close to the train station. I like my plaza and the town hall to be out of the way. This is my
favorite map.
But some people go to the island a lot and want their Retail close to the dock. Some people like their villagers all spread out everywhere. Some people like their beaches to face the other way. It all boils down to personal preference.