I know very little about getting tickets but plenty of people here will give you informed opinions.
I would, however, recommend avoiding the monster seats.
They are over-priced and every single one of them is obstructed view. The lower bleachers are always fun, Especially at night. I always liked the right field bowl.
There is a site on-line that will show you the exact view of the field from every seat in the house. Pretty sure it is posted on Talksox somewhere.
Boston can be a really fun place to visit. You should have a f***ing blast.