Continuing my tear through the alternate history travel guides...
Prime a civilized, sort-of-Edwardian TL, dominated by a massive British Empire including most of N. America, Africa, India, the Middle East, Japan, etc. Computers run on gears, electronics use vacuum tubes, airships are plentiful, and everyone travels by train. On the other hand, they also have nuclear power, cheap universal electrical public transportation, much more use of solar power than in our world, and advanced medical gene therapy and genetic engineering of food plants. (Babbage was more successful than OTL, and there has been a sort of low-tech internet mechanical computers, telegraph lines, and home teletype since the 1890s).
Constitutional monarchy is the norm in this world, as is a fussy, old-fashioned attitude that at its best manifests itself as a deep concern for professionalism and warm hospitality, but at its worst can be stiflingly elitist and stuffy. There is little censorship, but no TV studio of importance would have the poor taste to put on what passes for entertainment on our world's television. Keeping up Appearances is very important. Another notable thing about local thinking is an emphasis on style the notion of form subordinate to function is a blasphemy followed only by the crazy Integralists of the Italian dictatorship.
Population world-wide is rather lower than OTL, only about 2.2 billion effective contraception has been around for quite a while, and British America (~Canada + US east of the Rockies) has only about 120 million people. Indeed, most of the worlds nations have equivalents of the UK Bureau of Population, which through subtle propaganda and incentives prevents economically destructive population declines. (North America also includes Arcadia, a mostly French state in OTL Northern Quebec and the land part of OTL Newfoundland).
The world is generally peaceful, although a recent conflict between the empires of Siam and Vietnam over what is Laos OTL was only resolved by international negotiation after a bloody conflict. Mexico, including Central America, California and the Rocky Mountain SW, is more mestizo and Indian than OTL, and has an emperor. OTL Alaska and the Pacific NW is a Russian republic, independent of the Rodinia since the 30s. South America is mostly republics, and more politically fragmented than OTL: a former plethora of dictatorships have generally turned democratic thanks to Imperial carrots and sticks (the Empire has most of their economies in its pocket). Germany, ruled over by the Habsburgs (also rulers of Hungary), is placid and socialist. (Well, most of Germany. Prussia, a separate state, suffers from considerable tension between Germans and the Poles which make up 40% of the population).
Russia, after an unstable period of coups and military rule, is a shaky constitutional monarchy. France is also still a monarchy, while the Empire of China is perhaps the second most powerful political union on the planet, but is largely uninterested in events taking place outside its bailiwick and international affairs outside of trade. Around 70% of non-Chinese mankind is either part of the British Empire, allied with it, or economically intermeshed with it. A few small African states were never directly incorporated into the Empire, but have been effectively part of it since the late 1800s. Most of the Middle East has been absorbed into the Imperial system, and the Wahabii are just a kooky cult stirring up trouble in the desert interior of the Kingdom of Arabia. Indonesia, oddly, was Italian up until the 1980s.
There have been no major world wars in the last century, aside from a messy 1922 inter-German conflict which ended Prussian influence in Germany proper. Womens rights are approximately OTL in Europe and N. America, but male and female dress are quite conservative, pre-1920s generally speaking, although it is socially acceptable to wear (loose) trousers for women in professions which make skirts inconvenient. Language is florid, economics are liberal (in the old-fashioned sense) which is compensated for by an organized working class which in the Empire runs its own massive private insurance program. Environmentalism is a Big Deal, with most countries moving away from polluting fuel sources since the 1960s and energetic efforts to maintain unspoiled wilderness since the early 1900s: even street lights are designed to shine as much of their light down as possible, to minimize star-obscuring city glare. Television is only just starting to catch on, but radio theatre has been popular since the 1930s, and movies have been around almost as long.