What a fabulous adventure for you!
Before I moved across I thought there would be only two things i would struggle with: the language and remembering to drive on the left.
After five years here, I can honestly say those two were the easiest. I barely even hear accents any more.
There are little things that make you feel you are slightly going mad. Things seem to be opposite. Or just different in a way to slightly throw you off balance. Things like toilet handles on the other side, or salt and pepper shakers with opposite numbers of holes, light switches that toggle the other way to turn on/off. Do be carefull crossing the road because you won't instinctively look in the correct direction at first!
You'll learn quickly which words to use or not to use. I'm at a stage that I'm now forgetting which word is US and which is UK. However, the folks here have been so Americanized with TV shows, they will know what an elevator is, and a hood of a trunk and pants, sweaters, etc.
Spelling may also trip you up at the beginning. I am using British software, so spell checking is British. The pointer highlighted airplane as being spelled wrong. So I thought, what the..? I looked it up in the British dictionary I have and it wasn't there! So I asked my husband; I felt I was truly going insane. He spellt "a-e-r-o-p-l-a-n-e". I would NEVER have imagined. Same thing with tire/tyre, aluminum/aluminium etc. etc.
What I find hard to understand are not the words, but the meaning behind the words. Things are said that seem very offensive to me, but turn out to be how they are said and understood in this country. For instance, understatements or sarcasms can be misinterpreted. However, if this happens, just ask! (They'll love to hear your accent just as much as you love hearing theirs.)
Hard to make friends? Hmmmmm. Yes and no. I tend to keep to myself. No one is going to come and knock at my door and ask if I want to go out and play. I know, however, that in times of me making efforts, people here are warm and genuine and would do anything to help. Marvelous people. You just have to scratch the surface. I may not be speaking for larger city areas, however. But where I am, the proportion of non-Brit people is extremely low. I'm forever being told by perfect strangers about their holidays, past and future, because they ask where I'm from (I guess it's my accent
). Those instant conversation starters don't happen with the average Brit over here.
Have fun...you're already starting on the right road by tracking this sort of information down before you come.