Use the coastline as a loose orientation rather than a fixed itinerary. One scenic walk, one older district, and one seafood meal can be enough for a day.
Watch the season and wind
The same waterfront can feel entirely different with temperature, crowds, and wind. Pack layers and leave the most exposed walks flexible.
Look beyond the main shore
Smaller neighbourhoods and local markets give the city more texture than a single promenade. Use public transport or a short taxi ride to widen the radius.