For all of you who are new to leos or need help with one you already have, I hope this helps. I spent a couple days writing and planning this on paper, so here goes.
INTRO: Leopard Geckos (Eublepharis macularis) are a species originating in the desert areas of the Middle East. This species has eyelids, which is very rare among geckos. They also lack adhesive pads on their feet, so they cannot climb smooth vertical surfaces. Most leos sold today are captive bred so as to prevent wild-born disease. Leos basically are quite large (see section below) and have a yellowish-tan background color with black or dark brown spots covering their whole body, except for the whitish underside of their body. Other varieties with other coloration exist. Leos store fat and moisture in their tail for survival backup. The Leopard Gecko is well on its way to becoming the most popular lizard pet because of its low maintinence needs, making it an excellent choice for beginners and kids. One of the leo's best features is the fact that it only defacates in one corner of it's enclosure.
SIZE: Female leos can reach 7-9 inches long, while males grow to about 8-12 inches. Normally though, they are unlikely to grow quite as big as a foot in length, except in the wild, but if given the proper care and plenty of room, it could happen.
HOUSING: An adult leo requires a glass fishtank-like enclosure of at least 20 gallons. You should make sure it is long, not tall, as leos appreciate lots of floor room to roam. Since leos are unable to climb glass, you shouldn't have to purchase a top for the enclosure, unless the enclosure contains large objects that could allow a leo to climb high enough to escape.
SUBSTRATE: Most substrates, from newspaper to crushed English walnut shell, should be safe enough for use with a leo, although I wouldn't recommend using any substrate with any type of wood or tree bark in it small enough for them to swallow, as this could cause fatal impaction (see "Special Concerns" section below) in the leo's intestinal tract if swallowed. Also, don't use calci-sand, as serious intestinal impactions seem to occur alot with this sand. I highly recommend crushed English walnut shell, which if often sold in large bags for bird cages. It can very well cause impactions, but something about it makes leos hate getting it in their mouths, therefore never swallowing it, in my experience.
DECORATIONS: Leos appreciate fake rock decorations or driftwood as long as they have no sharp edges. A necessary decoration is a hiding area. This can be anything from a purchased rock dome to even something as practical as a butter tub with a smooth-edged hole cut in the side. Beware of rocks, or anything else, for that matter, from outdoors. Before using these, rinse them thoroughly in hot water first so as to kill off any parasites.
HEATING: An electric reptile heat pad is highly recommended for a leo enclosure. This can be purchased at most pet stores. Simply place the heat pad carefully on the underside of one end of the leo's enclodure, according to the instructions. Be sure that the heat pad takes up no more than half of the enclosure ground space, as they like to have a cool end of the enclosure as well as a warm end. Also, be sure the area heated by the pad isn't occupied with a water bowl (see "Watering" section below) - the heat could cause the water to evaporate quickly - or the hiding space - the heat could build up to uncomfortable levels in the hiding space. As long as the enclosure temperature stays within 75-95 degrees Fahrenheit year-round, there shouldn't be much of a need for a heat lamp. But if it indeed does get too cold for the leo, simply purchase a basic spotlight fixture and get a nocturnal reptile heat bulb from a pet store to fit it. Make sure the bulb is for nocturnal reptiles, as leos are indeed nocturnal and do not appreciate large amounts of light. Leave this heat lamp on, clamped to the rim of the enclosure, any time that it is needed (when the temperature drops below 75 degrees Fahrenheit. You can measure temperature with a simple stick-on fishtank thermometer). Be sure not to place the lamp directly overhead the heat pad - this could dramatically overheat the area. Rather, place the lamp slightly off the edge of the heat pad-heated area, as long as it doesn't heat the cool end of the enclosure.
SEXING: The best way to sex a leo is to turn it over and look between the legs, just under the anus. There should be a V-shaped row of pores. These pores will be more prominent on a male, especially an adult. Also, adult males secrete a waxy substance through these during breeding season to mark their territory. A male also has two bulges (hemipenes) in the area of the pores.
FEEDING & SUPPLEMENTS: Feed babies and youngsters around ten baby crickets, which you can purchase at some pet stores or bait and tackle shops, every day. Those crickets should be dusted in calcium/vitamin supplement repltile cricket powder (cricket dust) at every feeding. This should be available at most pet stores. For adults, feed 4 to 7 adult crickets every other day. Dust the crickets at every other feeding. Prior to feeding, keep the crickets in a seperate enclosure. Also provide them with a bit of fish food to fatten up on and a few slices of orange, potato or a capful of water to receive moisture and vitamin C (if slices of orange) from. The nutrients that the crickets absorb by eating the fish food and orange slices will be helpful to the leo when he/she eats them. When you buy crickets, buy a couple dozen and take out as many as you need at each feeding, keeping the crickets in a small glass aquarium or something similar prior to feeding them to the leo, as said before. Remove any uneaten crickets from the leo's enclosure, as uneaten crickets may gang up on the leo and actually try to eat it. For larger crickets, if they have large legs or wings, try to pluck them off so as not to prove difficult in digestion. Sometimes the leo may need a little extra calcium, so always provide him/her with a small dish of cricket dust in the enclosure. The leo will get accustomed to using this as a source of extra nutrition if needed. So as to provide your leo with a varied diet, also try to feed him/her mealworms occasionally in the place of crickets. These can be purchased at a pet shop as well. Be sure to gently crush the mouthparts of the mealworms prior to feeding so they don't chew the insides of the leo after being swallowed.
WATERING: Always provide your leo with a Petri dish about an inch deep containing about a half inch of clean water (tap water is fine). Give the leo fresh water at least every other day. I also have a toothbrush that I use to scrub the slimy residue out of the bowl every time I change the water. As said before, do not place the water bowl on top of a heat pad-heated area of the enclosure. When a leo sheds its skin, it will need extra moisture; when the leo starts looking gray and faded, place a clean, wet mesh sponge in the hiding area. The leo will sit on this during shedding so as to moisten and soften the old skin layer so that it will slip off easily without taking a toe or an eyelid with it. Be sure to remove the sponge after shedding is complete, as skin rot may occur from sitting on a wet area for long periods of time.
HANDTRAINING: To handtrain your leo, simply handle him/her as much as possible. After a while, the leo will become accustomed to this and will become much more tame. Do not be concerned when your leo makes a grunting or squeaking sound, as this is a defense mechanism. Be sure to be very gentle while handling, as leos are delicate, and never pick them up by the tail; the tail will detach, and the new one that will grow in will never look as good. Plus, leos are prone to infection when harboring an open wound (see "Special Concerns" section below). Always be sure to wash your hands thoroughly with soap and water after touching the leo, as you could receive Salmonella from not washing your hands after touching a reptile. I don't usually wash my hands after handling my leo simply because I am quite positive he doesn't have Salmonella, as I've handled him without washing many times and never got sick. I strongly discourage letting your leo crawl on the ground outside, for two reaons: A) they tend to lick virtually everything they come across, so they could, in turn, pick up deadly parasites that way, and B) hawks and other predators are always on the lookout for prey.
CONSTIPATION: If your leo suddenly stops eating and/or defacating for an extended peiod of time, it may be a growth spurt (if the leo is young) - during which they stop eating and defacating - or constipation may have occurred. I would advise that you fill a container with about an inch of lukewarm water and place the leo in there, holding him/her there if you have to, head above water, and leave the leo there for about 10 minutes. Then take the leo out, dry him/her off, then massage the belly with your fingers for a little while. This should help loosen up the bowels.
IMPACTION: If all the signs of constipation occur accompanied with dark blotches in the belly, an intestinal impaction may have occurred. Not much treatment can be reccommended for this, except possibly the constipation treatment listed above and mineral oil (seek the help of a veterinarian with knowledge of reptiles for advice on this).
SEVERED TAIL: As with most lizards and geckos, leos will "drop" their tail if they are grabbed by it, as a defense mechanism. The original tail has bones, but when it's severed and it grows back, it's replaced by cartiledge and doesn't look nearly as good. If your leo's tail is severed, there is a high risk of infection, so find a spare, sterile tank and put newspaper in the bottom and keep the leo there until healing is complete, and try to handfeed as much as possible during this time instead of putting the crickets/mealworms loose into the tank with the leo.
Feel free to ask any questions regarding information not covered in this caresheet.