As with clothing on a person, the fit of building is particular to its site. Along with parking impacts, "fitting-in" is one of the most contentious issues with infill i.e. what does it mean? Does it mean copying the neighbors? (And that's assuming that the existing context offers any remote reason to copy.) How far do you have to go? How far can you go? Libeskind finally got his permit but the neighbors were sure not happy about this proposed addition to the Victoria & Albert Museum, which though it may surprise you, I think could have been made to work nicely and to "fit in" in the largest sense of complementing & complimenting its neighbors:
There is a role for spice, the exception to the rule, the raisin in the oatmeal. But iconic buildings (or attempts at them) can be easily be overdone — you just don't want too many raisins in the oatmeal, just Goldilocks amount, or else the exception will devour the rule. And it's also a bit embarrassing to hear someone say that they want to build or esign an "iconic" building. What lack of insight into what makes an icon. Icons are recognized, nor designed.
Sandy Ikeda discussed "fit" here. Karen wondered about it here. Now Jon Swerens likes to how the issue is handled in San Jose, California, where while it's not quite my "Let 'er rip," official policy is that cloning is not essential to fitting-in. The key element (as I read it) is simply similar site plan:
New construction may do so by drawing upon some basic building features — such as the way in which a building is located on its site, the manner in which it relates to the street and its basic mass, form and materials — rather than applying detailing which may or may not have been historically appropriate.