There's never enough time to write.
You've got a full-time job, or you write for clients, or you have to take care of your family. The self-publishing industry has opened up an entire new world to writers, giving them an incentive to increase their productivity. This means more author marketing, more book marketing, and especially more writing time. No matter what the distractions, most writers want and need more time to work on their books. It's not that they're not trying to find the time; it's just that they're looking at the time the wrong way.
Trying to carve an hour out of a busy day can look like an impossible chore, but almost everyone can find ten minutes here and there. Do this six times a day and be prepared for writing when you do, and you've found an additional hour in which to write. It's not a casual process; you'll need time management with programs such as Instant Boss, which strictly holds you to a schedule. Having the right equipment at hand is crucial, but the choice between a netbook or a tablet with keyboard is one you'll have to make on your own. Whichever one you choose, carry it with you at all times. Install a writing program like yWriter if you use a netbook for ease of writing, or go for a site such as LitLift if you're online with a tablet.
Once you're ready to write, the key is to jump into the process every time you take a small break. These tiny bits of time are everywhere, once you start looking for them.
After your shower and before getting dressed in the morning
After lunch, before getting back to work
During an afternoon work break
After work, but before your daily commute
During commercials while watching television in the evening
Right before getting into bed
Jump right into your writing every time you get one of these small breaks, and set a timer so you don't have to worry about watching the clock. Everyone's writing speed is different, but even if you only accomplish 100 words in each 10-minute break, you'll finish 600 additional words each day. That's over 100,000 words in six months, or the equivalent of two to three books a year, all in ten minute chunks.
It's not the ideal way to write a book, and most writers prefer having dedicated hours to practice their craft. But if lack of time is your excuse for never writing that novel or never upping your work production, it's no longer a valid reason. Try grabbing ten minute breaks throughout the day for six months and you may develop a writing habit that sustains you until you can find those large chunks of writing time. It's an efficient way to write a book without disrupting any part of your daily schedule.