There are two ways in which you can approach a Futuristic world type; you can base it on the real world but set in the future, or you can base it on a fantasy world, but incorporate futuristic elements into it that you don’t normally see in more traditional fantasy fictions.
Tackling the latter of those two first, you have got to be careful to distinguish between alternative world types and futuristic fantasy. Steampunk is usually alternative rather than futuristic because it is based on the real world but with changes. Take out the basis in reality entirely and you end up with a futuristic fantasy world. Essentially it is a fantasy type where you haven’t based it on history like Tolkien did, but more on science fiction elements and technology, like Star Wars. An example of mixing technology and magic can be found in the Rojan Dizon novels by Francis Knight, where the power source for technology is magic.
Then of course there are futuristic world types based on reality. From my experience, these usually fall into one of two categories; utopian or dystopian. Utopian creations where technology has bettered mankind and the world as we know it hasn’t been destroyed, but has been build upon and developed further can be found in creations like Star Trek. My favourite has to be the Robin Williams film ‘Bicentennial Man’. You get to see the world develop and grow for two hundred years, as a backdrop to a love story. It’s fantastic to see develop.
Dystopian on the other hand is usually more common to see in fiction, especially at the minute in YA Fantasy books like The Hunger Games and Divergent. This are stories set in our real world, but in a future where not very much of what we would recognise as our world still exists and the world is imperfect. There is usually some form of corrupt power exploiting the masses that needs to be brought down via a rebellion.
Science Fictions films and TV series use dystopian this a lot as well; a notable example that I enjoyed watching was the TV series ‘Defiance’. The town of Defiance is where St. Louis once was, as seen by the still standing St. Louis arch. The landscape of Earth though as been terra-formed a great deal by the arrival of the various Votan races who have settled on a now unrecognisable earth alongside the humans. What i liked about Defiance was the power play between the various factions as everyone struggles to survive. It wasn’t really about a revolution, it was about building a better world in cooperation with each other.
So when building a Futuristic world type, you do have a lot of options. You can make it based on reality or fantasy, and you can make it as perfect or as imperfect as you like. It depends on what you need for your story.