Writing about the future is a tricky thing, as has become abundantly clear in the past few years. The technological developments have come quicker than anyone could predict. At the same time, some of the predictions that were made have been shown to be beyond us still.
I've been thinking a lot about this in the past month, as I have been binging on the In Death series by J.D. Robb (Nora Roberts). The first book was published in 1995. In 1995 mobile phones were not as ubiquitous as they are today, I got my first one in 1998 and I was one of the first in my class (that said I AM only on my fourth mobile). Naked in Death (the first in the In Death Series) is set in 2058, which I am sure seemed very far in the future in 1995, but, this side of the turn of the century feels very close by. In the books there are several technological devices mentioned, "link" = mobile phones; "PPC" = Pocket PC; "disks" = storage devices for computer files; "laser fax". 18 years ago all these things probably seemed to be on the technological forefront. Today, with little kids with smartphones (you should see my niece, 2 and a half, with her mothers iPhone (this post was written in 2012, niece is now 3 and a half but still a wizard with the iPhone) these things seem positively antiquated. I mean , when was the last time you used a disk, even a CD to save documents on? I barely use a USB drive to save information on now, much more convenient to use the cloud, especially when I can have the same document appear instantly on all my different computers (I am definitely partially responsible for the average number of electronic devices being above one :D).
At the same time, these books have technology that we have yet to invent or perfect. Some of it would be nice (I would LOVE my own autochef). Other things would freak me out (cars that can fly! I have enough problems keeping track of what's in front, behind and to either side of me, I would NOT want to add above and below).
To my mind the best way is to create what you could call an alternate universe. Make it clear that it isn't an alien place (I don't mind aliens but others do). Roberts does this by creating a world where yes some events do mirror our world but others don't. For example September 11th is referenced in one of the books I recently listened to. However, Roberts has added "The Urban Wars". A war that is referenced as taking place in both the US and Europe but never quite explained. Although it isn't hard to see an uprising in our cities today, calling them The Urban wars and placing them before the adulthood of the main character in the series adds to the feel of an alternative or perhaps parallel universe. This helps me, as a reader, to "cover" the obvious technical differences, the differences where we are more advanced than what this future society is.