Well you have to first decide what is your favorite thing to do? Do you like to go to the beach, hiking in the forest? Siting at the local coffee shop sipping coffee while reading a book or the newspaper? Once you decide if that you can decide if you want the beach, park, woods, or a downtown city scape. There are so many amazing locations in Boston for an engagement session. I actually put together a board on Pinterest for clients.
I am a big fan of the Joseph Moakley Courthouse waterfront harborwalk. You get a great scene of Boston Harbor and at night it's amazing. See this photo
Then you have the harbor itself, which you can see here.
I am a big fan of the North End of Boston and the cobble stone streets.
There are so many amazing places for Engagement photos. People love to head over to Acorn Street on Beacon Hill, but it can get over run with people.
List of great locations: