Depends on how built up your town already is and how it's organized.
However, here are a few things I found in good-looking and high-quality towns in my time playing:
Chunk-wide roads, facing two ways (like some kind of hedge separating "lanes")
Some kind of divider between plots
Stone brick and cobblestone roads
Larger town staff plots
No moss in the plots
Keep "town squares" and "shopping districts" and "farms" away from residential areas
Town farms of some kind
At least one set of off-site homes were also quite common
If you want your town to be extra relevant, you can also try these things:
Make some kind of mega-build
Make the largest of something on the entire server
Have the most beautiful houses
I also found that many towns do not have very high taxes, if any, and that the higher the taxes were, in fact, the worse the towns got almost as if those 25% tax mayors are greedy lmao. As well, many towns usually have a pretty nice and large arena.