Find a few photographs of a giraffe in order to do justice to your subject, and always refer back to the photograph when making aesthetic choices. Giraffes are wonderfully strange and unexpected--even if you know what a giraffe looks like, you'll replicate a giraffe with the greatest accuracy if you have a picture to refer to.
The challenge of sculpting a giraffe--what makes the giraffe different from most other subjects--is that the long, thin legs will be difficult to capture, especially if the giraffe sculpture is to be standing on its own, as the legs will have to balance the body and long neck. Before you begin your sculpture, your giraffe will be attached to a base for balance or if it will rely on its four legs for balance.
Assemble a wire structure (this is known as an armature) to act as the skeleton of the giraffe. The armature include a wire down the center of the body, a wire up the neck and through the head, a wire for each leg and a wire for the tail. Connect these wires together by twisting them together at the ends; if you find it difficult to twist the wires together, you can adhere them to each other by some other means. Tape will suffice--note that the wire skeleton does not need to be terribly sturdy, because once the plaster placed over the armature dries, the wire underneath will no longer serve a function. A base is recommended for a plaster sculpture of this type, so nail the armature to a wooden plank.
To cover the armature, dip paper towels in wet plaster and wrap them around the wires. The wire structure you've assembled will be much thinner than the actual giraffe, so the paper-towel-covered wire structure is serving as a base to build upon. After covering the armature with the paper towels, slather on wet plaster. Build up the plaster on the structure until it is thick enough to encompass the body of a giraffe inside it. It should be thicker and larger than what you want the finished sculpture to be, as you'll be shaving away the plaster to make the shape of the giraffe. Allow the plaster to dry thoroughly over a period of 24 hours.
Once the plaster has completely dried, carve into and shave away the plaster with a utility knife and steel rasps to form the giraffe. Use larger rasps to shave off the larger chunks of plaster, and smaller rasps and the utility knife to cut out the smaller details. Only work on the details after you've fully shaped the giraffe.
Think of the giraffe as an entity that has been hidden inside the plaster, and you must reveal it. Refer back to the photograph of the giraffe in order to form the muscles and shape.
In this plaster method, you'll make a rectangular block of plaster and whittle it down into the shape of a giraffe. Use an empty, clean half-gallon paper milk or juice container. Unfold the entire top and open it up. Fill the container to the top with wet plaster, allow it to set for 20 minutes and then peel away the paper container.
Examine your block of plaster and envision the giraffe inside. Draw the giraffe on the sides of the block of plaster, if necessary, before starting to carve. With your sculpting tools (a utility knife, steel rasps or even objects found at home, such as a butter knife and sandpaper), shave away the rectangle to shape the form of the giraffe. Start at the top over the slope of the back, where you'll want to remove the most plaster as you carve out what will be the back of the neck and the slope into the back. From there, you can begin to form the top lump of the head and neck, then move down over the body and finally to the legs. When whittling and carving, patience is key.
You'll want to begin carving while the plaster is still relatively soft and moist inside, when it will be easiest to remove a lot of plaster in a short amount of time. Carve the finer details when the plaster is harder and more brittle. Take special care not to crack or break the legs when working on them.
The challenge of sculpting a giraffe from clay is getting the legs to support the body of the animal when the clay is wet. To start, you'll form a lump of clay large enough to encompass the entire giraffe and then allow the clay to dry out somewhat so that it becomes not quite leather-hard (the term "leather-hard" means that it's still moist inside but no longer pliable). This way, the clay will be hard enough that the legs won't buckle under the weight of the giraffe's body. When the clay is ready to work with (it will be quite hard but not completely unmalleable), carefully carve the shape of the animal out of the lump. Start carving at the top of the giraffe and work your way slowly down, first working out the general shape of the giraffe and then going back later to carve the details. Ordinary clay modeling tools--wire loop tools, wooden shaping tools and needle tools--will be sufficient.
Because the legs are thinner than the rest of the animal, they will be more prone to drying out; if they dry too quickly, they may crack or detach. Until you've finished the sculpture, keep the legs wrapped in damp paper towels when not working on them.
Dry the giraffe slowly when it's done. Remember to hollow out the body if it's thicker than an inch to prevent the giraffe from exploding when you're firing it in the kiln.