One of the hardest things about being a writer - at least a fledgling writer - is learning how to put other tasks aside and actually find the time, and motivation, to write.
First: time. There are lots of good books that teach you how to prioritize tasks so that you can achieve your goal. So the first task is to make writing a higher priority than say, doing the laundry. It's not higher than your bill-paying job, as you'd probably like to see some money and you won't be seeing any from your writing for quite some time even if you get a novel published today. But one of the biggest mistakes a writer can make is treating their writing like a hobby rather than a carreer. Writing is work. It's not something you 'tinker' with occasionally as the mood hits you. It's something you need to work on day after day, until you have a novel complete, edited and ready to roll. Even then you're not done. You still need to find an agent or editor willing to work on your behalf to get the book published.
You can find time anywhere - if you plan for it and use it when it rears its head. You can write on the subway, on your lunch break, in the morning or evening. Even if you can only write for 10 minutes a day you'll be writing and you'll be amazed at how much you have at the end of a month.
Stop waiting for the elusive 'perfect day'. You know the one I mean. That day when you'll have no chores to do, no friends calling on the phone, no part-time (or full-time) job calling you in on your day off, no distractions from neighbouring apartments or noisy traffic outside. No kids asking for help with their homework or if they can have a cookie. No spouse demanding time and affection. That day when you'll sit at your computer for 8 hours and simply write. All day. No exceptions. Because naturally when this day comes you won't want to eat. You'll have no need to figit in the computer chair you've just realized isn't as comfortable after 10 minutes as you thought. No desire to get a cup of tea or a snack or a smoke. Nope. You'll be sitting in that chair on your perfect day writing up a storm without interuption.
Well, some people may be able to accomplish that. It's certainly a goal to work towards - one where you can spend the day writing without being disturbed by the vagaries of life. But for the majority of us, this day simply doesn't exist outside or imaginations.
Which brings up point 2: motivation. It's easy to use the above perfect day as an excuse not to write. It's one of the best procrastination methods since that day will never come. At some point you'll realize this and then have to decide how to really get your novel written.
At Ad Astra this year a self-employed comic book writer explained a great way to do this. PLAN. Plan your time. Plan it so that everything you need to do gets covered. Need time with the kids? Plan it in. Need time to make dinner, work, meet with friends, snuggle on the couch? Plan it in. Just so long as you also plan in writing time it's all good. And plan the writing time second (after your 'real' job). It's a priority, remember. And if it's in your schedule you'll be amazed at how easy it is to keep to it, and get some good writing done. And it's fascinating how much time the day really holds - when it's used wisely. There are so many ways to waste time nowadays. Plan your week wisely and you'll see that you can do it all.