It's the bane of most yet-to-be-published writers: with everything else going on in my life, how do I make space to write?
I'm hardly an exception. Between requirements at the Day Job and personal obligations like heading to the gym, spending time with the spouse, taking care of household chores and the like, it can be hard to block out time for writing. Worse, when I've finally sat down with some writing time to use, sometimes there's just nothing left to pour onto the page.
This really comes down to priorities. If working on the novel is important enough, making time becomes simpler (if not necessarily easier). But there's a subtler level, too: none of us is infinite. We all have to marshal our time and our energy. Just because I've managed to score some free time doesn't mean that I'll be able to use it effectively. If I've been shorting myself on sleep (and I frequently do) or failing to take care of myself in some other way (eating well, exercising, keeping my personal life as drama-free as possible), I won't have enough left to do anything like a good job, or to get any sort of fulfillment out of the experience.
The temptation is there to gut it out, to stay up until all hours and bleed onto the page--damn the torpedoes! sleep is for the weak!--but I know that I don't accomplish much by clawing a few hours clear if my brain is tapioca and all I can do is stare at the screen or write journal entries about how I'm so tired and nothing's coming to me. People at work have a right to the best you can do for them; why is your novel worth anything less?
Summing up: one mark of having your priorities in order is carving out the time you need. Another mark is spending yourself wisely: if writing is important, do what you can to make yourself--your best self--available for it.