Sloth – A failure to do things one should do, or general physical or spiritual laziness.
The concept of sloth is probably the most recognisable to many authors, the biggest enemy and the deadliest sin of writing. It's not easy writing a book, the process can be inherently time-consuming and it doesn't always serve to set yourself strict deadlines for finishing the entire project.
Sloth can creep into the everyday habits of a writer without them even realising. Staring at a blank page can be disconcerting but it's no better or worse than staring out of the window for minutes at a time. Procrastination is one thing but there's a fine line between planning and research, and aimless messing around on the Internet. It's easy to let a day, a week or even a month go by without adding to your word count.
Once you decide to make the move from casual writer to novelist, most find it helpful to set aside time to work. The worst thing you can do is fail to keep that appointment with your work, or just do a few minutes because you're not in the mood. Many great novels are lost to the ages because they never got past the third or fourth chapter.
We all get lazy now and then, plus writing while uninspired is a tricky business. You'll thank yourself later if you stick to the task and try to get something down on paper though. Sometimes it helps to just write, paying no attention to form, style or context, just get something down. You'll find it a lot easier to edit than to create, even if you end up changing nearly every word. As long as you have planned out key points in the story, you know where you have to go next or eventually end up.
Being diligent and using your time effectively will help you train your brain and your body to accept the author's lifestyle. Sure you'll still want to get up in the night and write something amazing down, and you should, but there's a lot to be said for working in a disciplined fashion when you're well rested, fed and watered.
If you do have research tasks that require trips away from your desk, consider using them as a reward system. Don't make all those trips before writing, spread them out over the entire process, either by time or by word count targets. Then make a day of them, scout locations, line up people to talk to, find nice views to sit and make notes by. By the end of your trip you'll be desperate to get back to your desk and start typing away again.