My girls sleep a lot. At first Lucy never slept but gradually she fell into the sleep routine and now we (almost) always have great long naps.
I occasionally take naps with the girls... like on days when I'm extra tired because I drove home from Spokane in the middle of the night.
This is our current nap time routine:
1:00: lunch. Peanut Butter and honey on whole wheat, 1/3c goldfish crackers, 1/4 apple 6oz milk.
I've found that giving the kids the same lunch everyday helps them anticipate what is coming next. At first I thought that giving the kids the same thing would make them picky. It didn't, they eat pretty much anything.
After lunch, they clear off. They go potty and I wash their hands and faces with a hot wash cloth. Usually I can feel them already begin melting into the comfort. They all get a little drink of water even though they already had milk with lunch. Since I know they've had a lot to drink I don't ever ever given in and let them get another drink. The only way they don't get in trouble for getting out of bed is if they have to go to the bathroom, but since they've already used it usually it eliminates that problem too. Of course they'll try it every once in awhile but if they don't actually go, they know they'll get in trouble for saying they do. lol. They've each tried it once or twice.
After that they're put in bed, covered up, hugs and kisses, I say, "I looooove you! Have a good nap." and then I turn the blinds and go out and close the door.
Voila. Full, clean, hydrated, sleeping kids.
For me, if I am going to take a nap then I wait until they're asleep (like 3 minutes) before lying down. Otherwise they'll get up and I get frustrated quickly.
I set an alarm for myself for two hours. They kids usually wake up around then but I think it's important for me to be awake before they are, that way I can be happy to see them and I usually have a snack (pretzels, water, string cheese) for them on the table.