[edit] Steps

To get started you will need a mild facial cleanser, facial exfoliating scrub, 2-3 chamomile (or green) teabags, a face mask, oil-free moisturizer, a headband, and a towel.
Pull your hair off of your face using the headband.
Wash your face using a mild cleanser. I recommend Cetaphil, it's soft on the skin and especially great for sensitive skin.
Use the exfoliating scrub in a circular motion on your skin. I use Clinque Facial Exfoliator. It is easy to find in your local mall in the beauty section.
Pour boiling water into a big bowl and add the chamomile teabags. Put your face about 30cm above the bowl with the towel over your head to make a 'tent'. Stay there for about three minutes. After doing so, you must use toner/freshener. If you have oily skin, you should DO this only once a week, but for dry skin, repeat this twice.
Apply the face mask and leave it on for the recommended time.
Wash off the mask and make sure there are no traces left behind. Apply some light, oil-free moisturizer to your skin.

[edit] Tips

Make time for your D.I.Y facial once a week.
If you really want to keep your skin under control, the best thing to do is have a routine. Wash, tone and moisturize twice a day, everyday.
Apply a little tea tree oil to any really big pimples.
For super soft skin, apply the moisturizer while your skin is still wet, to lock in the moisture.
After you've done your facial, don't wear make-up for a few hours to give your skin a break.
Pick a face mask depending on your skin type. Clay masks are great if your have oily or pimple-prone skin. If you have sensitive skin stay away from peel-off masks.

Always make sure to test ANYTHING going on your face at least a week BEFORE a BIG DATE, or OTHER OCCASION! There's only so much that make-up can cover before you just look plain silly!