How can I keep a cheesecake from cracking?

To make a good baked cheesecake, I was taught the following, and it has ALWAYS worked:

• Start with room temperature ingredients.
• DO NOT over-mix. This is a significant cause of cracking, as the incorporated air tends to souffle.
• When baking, always bake in a bain-marie (put your cake into a water bath for insulation).
• Bake half an hour at 300° F / 150° C. Then, turn off the oven, open the oven door, and rest for 30 minutes. Then, close the oven and bake 30 to 40 minutes more at 300° F / 150° C.

My first pastry chef taught me this, and it always works.

Also, over-baking will definitely lead to cracking (due to the loss of moisture), and, as stated, over-mixing will as well.

Similarly to what was said by @mrwienerdog, temperature and cooling are the key providing your mix is robust.

Whenever I bake a cheesecake I tend to do the following:

• start with a short period, 10 minutes say, in a hot oven 220C (425F)
• then take the temperature right down quickly (leaving the door ajar to aid cooling) to a slow/very slow ~130C (260-270F) for about 40 minutes, or until it feels springy.
• then switch off and leave the cheesecake to cool inside the oven, slowly as the oven cools itself with the door shut

Using this method I've never had any cracks, the cheesecake stays very moist due to a quick "sear" at the start, then slow cooking and a slow cool-down to avoid cracks.

Another method to avoid cracking is the following: A couple of minutes after you take the cheesecake out of the oven, run a thin-bladed paring knife all round between the outside edge of the cheesecake and the inside edge of the springform pan, always with light pressure against the inside of the pan (i.e., away from the cake) so as not to damage the cake. This reduces tension forces inside the cake as the cake tries to pull away from the pan wall as it cools, thereby reducing the risk of cracking.

I bake cheesecake using the same first two steps as @Orbling, but I've always used the knife method, as I hadn't thought of slow cooling in the oven as another way to prevent cracking.

I have been making cheesecakes with cracks for years and I have finally found the answer thanks to a lot of people and a lot of reading. I bought a Lueke silicone spring-form pan and a 10" and 12" fat daddy pie pan. I sprayed the spring-form pan with Pam, put in the 10" pie pan, then into the 12" pan and added hot water to 12" pan and cooked according. I ran a sharp knife around the edge of the spring-form pan and let cool with the rack pulled out and oven off. Sounds like a lot of work but I did not have even a hairline crack and it is the most beautiful cheesecake ever and I know it will be delicious. Thanks to all who helped.