[font="comic sans ms"]there are many threads on this -- do a search and you'll pull up literally hundreds of tips and tricks!
your sleep is sacred! treat it as sacred and make sure that everyone in your household does as well. no waking you up unless the house is on fire, your mother is having a stroke, your child's school as been taken hostage by terrorists or a tornado is coming up the street! sos need to stay out of the bedroom while you're sleeping, so that means they need to gather what they need for the day and move it on out of there. no popping in to get a different pair of shoes or a clean pair of socks. no lying down to "nap" with you. no waking you up to ask if the dog has been fed, the child's permission slip has been signed or the electric bill has been paid. you wouldn't wake him up at 3 am for that, so why should he wake you in the middle of your sleep time?
keep your room cool, dark and quiet. get black out shades or curtains, or cover your windows with aluminum foil. (in the northwest, that will make neighbors and new acquaintences wonder whether you've got a grow room, so expect questions!) use ear plugs or an industrial-strength fan on high. (an ex-boyfriend once moved into my house while i was sleeping next to my fan, and i didn't hear a thing!) turn off your phone, turn off the ringer and turn the volume down on your answering machine. if there's a problem at school, they can call the child's father, step-parent, grand-parent or a close friend you've pre-selected. if you simply must be available for emergencies, get a separate cellphone or pager and make sure that anyone who has the number knows that if they call you and it isn't a dire situation, you'll be calling them back at "0-dark-thirty".
make sure you eat healthy. that probably means bringing your meals to work, since there's usually very little available in most workplaces. bring a meal, not just snacks. make time during your shift to sit down and eat your meal. and stay hydrated.
understand that everyone is brain-dead at some point during the night. well, almost everyone. figure out when your "brain-dead" time is, and schedule all tasks that require coherent thought (charting, for example) for another time. as much as possible, anyway. (i also have a brain-dead period during the day, but that isn't as well-accepted!)
and if you've ignored every other suggestion i've made, do not, under any circumstances, answer the phone while you're sleeping! dh has agreed to different long distance plans, costing us $$$$$ and i once accused my father of being a pervert. (when i asked who this was, he said "i used to change your diapers." i gave him a blistering tongue lashing and hung up. he still likes to remind me that i didn't learn all of that vocabulary from him!) worse than that, you might agree to some outrageous amount of overtime, volunteer work or to drive your child's entire class to the city for a field trip!