Separating the time needed to write daily is especially hard if you have a fixed job, family and social obligations, then, how do we get it?
An option is to cut down on the time we spend watching TV. But many times the reason we watch TV is that we are tired, stressed, and we just want to take a break and think about nothing. Writing in such condition is not recommended either.
Going to bed an hour later may help, if we are nocturnal beings. I personally have a hard time keeping my eyes opened after a certain hour and I generally devote the last part of my day to read (something necessary; do not change reading for writing because it does not work).
Many people find it useful to write in the mornings, on the contrary. The agony of getting out of bed an hour earlier is dissipated with coffee. Moreover, you will probably be much more alert that at night, the neighbors are not making any noise, offices cannot call because they are not open and sales persons have not begun their rounds yet, which means there are less distractions.
But of course, this depends on what works best for you. You only need to make sure that when you write, you do so intelligently.