I've just discovered an excellent website for writers, at www.spreadtheword.org.uk. One of the features on the site is an article by novelist Maggie Gee ("The White Family," and "My Cleaner") about finishing the novel. Here's a little part of her advice:
"If you're stuck, or bored, with a particular chapter, either bring it to an end, or move elsewhere. Try moving to another character, or a part of the plot that really excites you. Write the end, if you like, so you have somewhere to go. I very often write the end of the novel first, so there is somewhere for me, on my rope, to swing to."
I'm quite intrigued by that approach; I've heard some novelist say they have to know how the story ends (while others say they would be too bored to keep writing if they knew the ending) but it's an interesting idea to actually write the ending first. Maggie Gee stresses in her article that she's only discussing what works for her, she doesn't presume it will work for everybody else, but it's another useful strategy to consider if you get stuck.