Start from Warwick Avenue tube station and you'll be at Little Venice, named by the poet Robert Browning who lived overlooking the canal in the 1800s. It's very picturesque here so do stop and take photos and maybe visit the Waterside Cafe before starting the walk. You want to be on the opposite side to the cafe to walk to Camden.
Little Venice to Camden Walk
Waterscape (British Waterways) have many canal-side walks and these photos are from part of this Little Venice to Camden Circular Walk. I chose to stop at Camden and not return to Little Venice. It's not a strenuous walk, it takes 1-2 hours, and my four year old managed it with minimal complaints. Be aware there might be diversions along the route but there are always directions posted so you won't get lost.