Porto, just across the river, is famous for its Port wines. Vila Nova, on the other hand, is famous for the caves in which the wine is stored during its aging; most of the distillers offer tastings and tours. The municipal gardens here, the Jardim do Moro, are a good place to rest before advancing into Porto.
Upon arriving in Vila Nova de Gaia you are presented with a large roundabout and tram terminal. Continue along the tram line; it is a straight walk all the way to Porto.
When you get to the end of town, the bridge over the Rio Douro has two crossings. The upper crossing will take you to the Sé Cathedral in Porto, and the lower one will take you to the riverfront in Porto. It is advisable to check the location of your accommodation before choosing which way to go, as taking the lower route (which is the marked trail) will require you to make up the elevation difference later.