I've done this to the UK and then to Canada with a teenage boy. Both were difficult transitions but by the end of the first year, he found his feet and thrived. We moved to the UK from Southern California.
In the UK (moved at 11, in middle school): football saved him but he is extremely committed and passionate and played at a high level. He is also very academic and so that helped him make some really good friends. there seemed to be two paths where we lived: one academic and non-drinking and the other non-academic and drinking (football seemed to land in this category). Activities that DS and his friends did a lot of were movies, concerts, paintball and hanging out at ours or at friends' houses. It was pretty simple to organize a group for paintball which was a great bonding experience for them. This was much better than the other alternative which was hanging out in the Sainsbury's car-park getting snogged.
He did go through some pretty rough teasing in the first year but he made it through. It also helped to get him involved in school trips - he went to Iceland, Barcelona, the battlefields in France and Belgium and a few other small ones. But I think what clinched it was sports and being a good athlete; because of that, he gained positive attention and even the bullies eventually got onside. He also played badminton, ran cross-country and track. Diversification seemed to work for him! One of his strategies was to befriend the bullies. How he did it, I don't know but whatever he did, it worked!
Moving the other way to Canada, he was 16 and he spent the first 6 months mourning the loss of English football but something clicked in the last few months and he has found his place here. I think the adjustment period this time was much harder than moving to the UK, but he got over it much much more quickly. He got to decorate his room how he wanted it (in Claret and Blue Aston Villa Colours
), hung the Union Jack, and he has his own laptop so he is in daily contact with his best mate and all his other friends on Facebook. Thank God for social networking!
What finally make it click for him was that he saw where he wanted to go and he is doing what he has to to get there. He also found a group of friends who are heading in the same direction. For my DS, having a solid direction that he can see has been the most important thing.
Oh and school uniform: best thing ever. Even my kids agree! We had a skateboard park in our neighbourhood - I don't know if Edinburgh has the equivalent. I'm all for anything that keeps the kids occupied and away from just hanging about getting ripped.