Oh, so many things but what I really wish I had taken/sorted out before I left the UK is the document from DVLA which makes your drivers license international as well as the certification from DVLA that my drivers license is authentic. I have found it a hassle to obtain these documents from here, mainly because I no longer hold a UK bank card and therefore could not pay the 10 pounds and 5 pounds respectively for these documents and so had to ask someone in the UK to do it for me.