Pompeii is thought to be the wealthier commericial/trade towncompared to Herculanuem - which is thought to be a lower-class resort/fishing town. This is seen in the wheel ruts in the roads of Pompeii, particularly along the Via del Abbondanza, suggesting alot of commercial traffic and goods travelled through Pompeii. There's no evidence of wheel ruts in Herculaneum. Pompeii also has more grand/decorative architecture eg: fountains and it also has mor public buildings eg: 4 baths compared to Herculaneum's 2. However, much of Herculaneum remains unexcavated.
There's evidence Herculanuem had better sanitation than Pompeii. The strees of Pompeii has stepping stones, whereas Herculaneum's didn't. Herculaneum had an effcient drainage system with an underground sewer.
Both towns followed the structure of GReek town planning and contained buildings of Roman towns eg: palaestra - suggests they followed the Roman way of life.
There's heaps more, but I hope what I have written has helped. The key is to write about the features of the streetscapes and say what they say about the town , it's function, people's lifestyles etc. Go beyond just describing what the features are and what the town looks like, that is what will push your marks up.
