Try not to just extrapolate current trends - rather, see beneath the surface to the underlying nature of how things change and envision what effect those deep societal currents with have on society. Technology changes, but not in the ways you expect -the applications and consequences are always chaotically coming out of the blue. Build me your convincing vision of 2050 - if can be as utopian, dystopian, or mundane as you like, but make it interesting and visionary.