The longer I am here, the more I feel I fit in. When I first moved here, I couldn't even go to Asda without being asked about why I was here (it seems aspects of my personal life are completely fair game; where my husband is from, how we met, about my family back home. It annoyed me at first, but I'm used to now.) Now, I don't think about not being 'from' here. There are odd days where I'll be walking to work or something and it sorta hits me and it is now rare for comments to be made about me being over here.
Other than one experience with a member of the public at work (I could have filed a racial harassment complaint about it, but being a typical Minnesotan I didn't want to cause him trouble) I haven't had any negative issues with my being American.
In 4 years, I have run into 3 Americans here (other than tourists). I think that has helped with fitting in as my only interactions are with people from here. I do love it when people ask me for directions and then get this weird look on their faces when I put on a thick American accent to give them correct directions lol.
I have found that being an atheist is more excepted over here, but I do struggle with the almost ingrained Christian observances. It really really bugs me that the buses where I live don't run on Christmas Eve, Christmas Day and Boxing Day (although I do realise that Boxing Day is not a religious holiday) and that shops close on Sunday or have limited hours. Where I lived in the US religion was seem more as a personal thing, not something that should affect non-belivers, shops would pretty much be open the same hours on a Sunday (definitely wouldn't close at 4.)