By: Simon Tisdall, Toby Helm, Morwenna Ferrier, John Naughton, Vanessa Thorpe, Rupert Jones, Max Olesker, Wendy Ide, Sean Ingle, Jonathan Watts
The new US president will almost certainly bring unpredictability but several themes will dominate the year ahead. Observer writers offer their guide on what lies ahead in politics, film, fashion, sport and more