People are all talking about literal designing patterns and I just wanna talk about layout.
First get your themes situated and what you want your town to be about. Decide what you expect in your town's geographical features. Do a good name for it and for your mayor. About everything you do in your town should be done with your theme in mind.
After deciding where to put Mayor's house, probably the first thing you should do in a town is
figure out where you want your main road/pathway to go. Start with the important places and work out the best ways to get from one to another. Cut down any trees and get rid of any villagers in the way of your ideal path. Finish laying your path and you can then move on to either making your own path designs or getting the sewing machine and finding some on Tumblr.
Next you get to worry about
where to put your perma PWPs, and whether you even want some of them. Again, remove unnecessary obstacles in the way of the places you wanna put them.
Then, work on
where you want your villagers to go, and who you want your villagers to be. Get your dreamies and plot reset and all that.
After that's settled, you can work on the normal PWPs and which ones best go with the theme you're portraying in your town. Decide where they would best go. Get your nature stuff out and start planting.
While you do this, work on the things you want your house(s) to represent, and whether you want or can fit multiple playable characters in your town.
At least, this is how I would properly do it. I'm kind of in the process of making a guide of my own. Not trying to be bossy, just giving advice on where to start
