I've unearthed an interesting technique in the last few days of writing. I've stopped when I'm on a roll.
When I get in a groove and I'm already well over my goal for the day, I have found that it helps out extremely in subsequent days if I just plain quit. That's different from when I started. At the outset of typing this novel, I would write and write and write until I had completely wrung out the sponge.
Now I shoot for my goal, write past it if I'm on a little bit of a roll, and then stop. If I still have fuel left in the tank, that's great. It keeps the ideas churning in my noggin until my next writing session. Some days, that turns into another writing session later on in the day. Other days, I just hit the ground running when I start rolling the next day. I'm not tapping my fingers thinking 'Where the heck do I go next?'
But what if I lose it? What if I forget where I was? Well, if I forget where I was when I sit back down at the computer, I have bigger mental problems than just coming up with believeable characters. That's why you write every day, so it stays fresh.
Everybody talks about making sure you leave your readers wanting more - making it so they're turning pages. Well, I'm discovering this for the first time, too, so I might as well leave myself itching to get to the next part.