Here's a quick tutorial:
You will need: Wig cap*, Alginate, Water, Cling wrap, a cotton ball and a friend maybe to help you.
1. Prepare your head by pinning up your hair out of the way, as it can get pulled out if its stuck in the alginate. I prepped mine the same way I do for a wig, including wearing a wig cap.
(That crazy hair colour though, is another story!)
2. Next, you want to cover the area around your ear (under it, behind it, around it) with cling wrap, to protect your hair. Cut a small piece (2x the size of your ear) of cling wrap out, then cut a slit in the middle, and slide it over your ear. finally, tear off a little bit of the cotton ball and stick it into your ear canal (don't shove it in, but enough down that it isn't interfering with the shell flaps of your ear.) This is to protect against any alginate accidentally dripping into your ear canal.
3. Mix your alginate as per instructions (equal parts alginate powder and water). Alginate dries pretty quickly so you have to be fast, but still careful. My lot took 45 seconds of furiously stirring to turn the acceptable colour (white, but other alginates may turn different colours, so read the instructions!), and then it was time to apply.
(We applied this lot too soon, and it was still a little too runny and ran down my face!)
4. Applying the Alginate. Make sure your alginate is of a pasty consistency, the proper colour, and there's no lumps of powder. After trial and error, we discovered that lying my head sideways on the table while pouring on the alginate was best to stop too much running. Pour your alginate (or scrape it) onto the ear, using your fingers to get into the crevices and behind it. Make it as thick as you can all over, as thinner sections are prone to ripping when removed (We ripped one and had to do the right ear twice). Also work quickly, as the Alginate will set in 30-60 seconds. You will know its set when it is a rubber feel, and the surface isn't tacky.
5. Time to take it off! Using your fingers, very VERY gently tug the cast off your ear, from front (tragus) to back (helix. google it :P). Go slow. Let any stuck cling wrap come off with it, you can pluck that out of the cast later. I emphasise gently because alginate is delicate, and thinner sections will tear easily if you're not careful. you can see in my end result picture that even mine has a couple tears, but nothing that will be a problem when it comes to casting. Also, the cotton bit stuck in your ear will probably come out with the cast, thats okay. Once it's off your ear, gently pull off the cotton bit and any remaining cling wrap.
Tada! You just made a cast of your ear! Looks weird huh, all reversed like that. Is that a hair? ;D