The other day, I got a lot of yard work done. I have a large lawn at the house I rent and there are several bushes surrounding the house.
Because the lawn is large, and I don't have a riding mower, I have to stop in between sections of mowing to take a breather and drink some water. When I do, I observe how much of the grass has been cut and how much is left. It reminds me that, while there is still plenty of work to finish, that I have already accomplished a lot. And though I sweat a lot and may sometimes get frustrated, looking at what I've done helps me remember to finish the task.
It's the same with the bushes and growth I've cleaned up along the sides of the house. I can only stuff so much trimmed shrubbery into the trash bin that gets rolled to the curb each week for pickup. Once again, I can see that there may be shrubbery that still needs trimming, I can observe how much I've already trimmed and the progress I've made. Though I have to wait a few days before I continue, I know that some work is out of the way and I'm that much closer to finishing the job.
Most tasks are not finished in the blink of an eye. They take time to complete, sometimes longer than we might want them to be. But the important thing is to examine how much you have completed, giving you that reminder that much has been done and that the rest will come with time.
I find it helps with writing to keep track of the words you have already written. Keeping a running tally of how much you have written each time you sit down can be a good incentive to getting the rest of the work done. You'll sometimes find yourself amazed about how much you have completed, which should motivate you to keep going until the work is complete.
You might not get to it in one day. Few novels are finished in a day. A short story, on the other hand, should be finished in a day, but sometimes you may want to take a break from that writing. Writing 10,000 words in one sitting isn't easy, just like mowing a large lawn in one sweep may not be easy unless you've got the right tool for the task. And for most of us, I suspect we aren't planning to write 10,000 words without stopping.
But regardless of how you approach your writing, remember that what you have accomplished is what's important. Knowing how far you've progressed with a work might be the incentive you need to finish the job. Before you know it, that job will be completed and you'll feel good about what you have accomplished.