One of the best sleep lessons I ever received was from my high-school diving coach, and I figured it was something I should share. He would always tell us that getting a good night sleep before a competition wasn't all that important. Instead, it was the night before the night before the competition that really mattered.
Part of the logic here is that if there's an important event, you may be a bit jittery the night before anyway, so it's best to figure you may have a hard time sleeping, even if you're trying to get a good night sleep.
I don't have any scientific evidence, but anecdotally, I've noticed that this is really true for me, and seems to be the case for business as much as it was the case for sport.
I've noticed that if I'm not in a great mood or am feeling pretty tired, it's almost certain that two nights prior I didn't get enough sleep. Maybe this is why a lot of people are crabby on Monday?
Likewise, I'm able to function really well on very little sleep the night before some important thing, as long as two nights earlier I got a good amount of sleep.
Maybe you'll find this tip as helpful as I have, so give it a try. If you have an important presentation, or sales meeting, interview, or whatever; don't worry too much about getting a good night sleep the night before.
Instead, worry about the night before the night before.