Between Christmas and The Lord of the Rings, elf ears are quite popular. If you walk into any costume shop you can buy latex elf ear tips, but these are generic and are often don't look real. However, with supplies from the same costume shop you can make custom elf ears that are designed for the person wearing them. They are easy to make and look much more real than something out of a package.
Cut a hole in a piece of cling film the size of a two pence coin.
Put the cling film on the side of your model's head, pulling her ear through the hole. The cling film will protect her hair.
Sculpt an ear tip onto her ear with nose putty, available at any costume shop. You don't need any tools, just use your fingers. Nose putty is sticky, so coat your fingers with a little baby oil to keep it from sticking. Try to follow the curves of her own ear to make the tip look like it is part of the ear and not just stuck on top.
Smooth the putty's edges into her skin with more baby oil and buff out any noticeable imperfections. Be sure to smooth the putty on the back of her ear as well as the front.
Gently blot the tip with a tissue to remove excess oil.
Dab liquid latex onto the ear tip with a make-up sponge, extending it onto the model's actual ear, front and back. Allow the latex to dry, then add another layer. You want six to eight layers total, each one stopping a little higher than the previous so that the edge stays thin.
Powder the latex with baby powder to prevent it from sticking to itself.
Carefully peel off the latex ear tip, powdering the inside as you go.
Remove the putty from the inside of the latex ear tip.
Repeat the entire process for the other ear. If you feel comfortable with it, you can do both ears at once to save time.
Glue the latex elf ears back on with more liquid latex or spirit gum. If there are noticeable edges, dab a bit of liquid latex over them. Since the nose putty will only be on your model's ears for a short time, there is no need to glue it in place.