You don't necessarily need to set aside hours upon hours every day in order to produce a decent word count output. If you could take a peek into my life via a hidden camera, you would definitely see I don't have that! With a houseful of kids, a husband who works primarily from home, a bunch of animals and a garden, I can only afford to spend a fraction of my day on the computer. Nevertheless, I published four novels in 2017, and one in 2018. So here are my top tips on writing fast:
1. Stay focused. Once you sit down to write, write. Don't get distracted by your email or Facebook, don't be tempted to check Twitter just for a second. My suggestion is to write offline... oh, and put your phone aside, on Quiet mode. No snacking during this writing sprint, either! Rather, prepare some goodie in advance and reward yourself once you've finished your set time or word count goal.
2. Outline. Outlines are the best friends of the focused writer. It's like a map; once you know where you need to go, it's a lot easier to plunge forward in that direction without stepping to check out side-trails. Do this both on the macro (major plot arc) and micro (chapters and subplots) scale. If you tell yourself, "Now I'm going to write the dialogue scene between Benny and Mary, and I give myself 30 minutes to do it", it's a lot likelier that you'll actually have something to show for it than if you just muddle around.
3. Don't edit as you write. This one is particularly hard for me, as my inner editor never quite falls asleep, but I've found that it's really counter-productive when working on a first draft. Allow it to be flawed, and leave all the nitty-gritty for the editing stage. Remember, if you don't finish that first draft, you won't have anything to edit!
More suggestions for writing like the wind and making most of the time you have can be found in my free, nonprofit e-book, Writing Tips for Busy People.