First of all, let's work on the psychology first. Be sure to fuck up your relationship with food from the start. You want to make yourself as neurotic as possible about food, eating, kitchens, cutlery, refrigerators, restaurants, and hey, why not stretch this out even further and start hating the actual source of foods, in other words the actual animals and plants. I myself am utterly opposed to factories. Any kind of factory. Even pillow factories, hell they're all the same. But you! Spread those bad thoughts! Hate that chicken!!!! Unless of course, you're going for the sympathetic, oh the poor animals, vegan slant. That's a good one too.
Firstly, reaffirm your mission. Immortalise it. Buy a fat, blank notebook, this will become your own personal anorexic sanctuary of sorts. Write down WHY you want to lose weight. Be sure to include things like how you will feel when you're 10lbs lighter, the glorious clothes you will fit into, an occasion that you would like to be thinner for like your sixteenth birthday, etc. Give yourself a final goal, and break it up into several, smaller, goalpoints. For example, if you weigh 140lbs and would like to eventually be 90lbs, list points along the way which signify a victory for you. For example, 130lbs, and then 115lbs, then 110lbs, then 100lbs, and so on. Re-read this again and again for inspiration. You will be using this notebook later to create tackytown anorexia-inspired collages and other paraphernalia.
Visualisation. Following the same strain as NLP, or Neuro Linguistic Programming, we must use the principles of association to retrain your consciousness, and sub-consciousness, to turn food into one of the greater evils of the world. (Read: the greatest evil!!) Start by associating food with disgusting things. For your first ever fast, it may be helpful to draw pictures of juicy red apples, somehow morphing into giant dead rotting pigs. Plaster these all around your house, preferably on the food itself. Never underestimate the power of images. Put pictures of fat girls on your fridge, or better yet, pictures of yourself; you're pretty fat. Conversely, stick pictures of rakish models everywhere you can see them, for inspiration, and a bit of productive self-loathing. Also, practise writing things like "I'm fat" over and over. You want to drill this into your brain. "I will be thin" is a good one, as well as other "I will" affirmations. These are positive statements and very conducive to big time weight loss.
Now create a list of suitable punishments either for thinking of food, or for caving in and eating food itself. A good one to try is to keep a rubber band on your hand and flick your skin whenever you think of eating. Eventually you will have a swollen hand, and a shrunken body; you will have ceased thinking of food so much. Other punishments include ridiculous amounts of exercise, purging, self-mutilation, isolation, basic denial of necessary comforts such as blankets on a cold night, or shelter when it is raining.. or simply menial, disgusting tasks such as cleaning the bathroom. Remember, you need discipline.
Invent pain and hassles for yourself. Trick yourself into believing your life sucks. Be mean to people so that they instigate fights, just to make you constantly on edge, or nervous, so you cant eat. After all, you'll be light-headed and dizzy, and irritable from not eating, so you have an excuse. I used to love when dad got mad at me because it meant I was so upset I could not eat. Become an angst ridden teenager. You'll be making yourself nauseous from worry and self hatred in no time.
Find another anorexic to consort with. Whether this be in real life, or on the internet. You can swap tips and indulge in your little sordid anorexia world together, force each other to exercise, pat each other on the back when you reach goals, etc. You want to completely surround yourself with all thoughts of anorexia. Find pro-anorexia websites, or create your own. Sign up for one of the dozens of pro-anorexic mailing lists at Yahoo! and you'll be bombarded daily with like minded individuals.
Now, immerse yourself further in anorexia propaganda, read anorexia or otherwise 'thin' inspired literature, listen to anorexic music, watch as many triggering films as you can get your delicate little mitts on, look up to very thin hollywood stars and supermodels. Also, visit as many of the aforementioned pro-anorexia sites as you can to get a bunch of quotes and 'mantras' to write in your anorexia notebook, and repeat inside your head daily. I have compiled a list of such sources of 'thinspiration'.