This site will have almost everything you need to know
http://www.axolotl.org/
Here is some of the basics i tell buyers:
Make sure you cycle your tank before purchasing your axolotl which means you will need a freshwater master test kit for setup and ongoing care.
1 axolotl needs 2ft of space, 1ft extra for each extra lotl (as a general guide only as tank widths vary)
Do not use gravel or any other items like rocks less then aprrox 1.5x the size of the axolotls head or your risk harming your axolotl. However sand is okay.
Have plenty of hides for your axolotl and use low lighting if any.
Feed on average every 2 days for adults as much as they like just keep an eye out that they don't over indulge. Their tummy should be about as wide as there head as an indication, too much bigger then you are over feeding.
They should only be housed with other axolotls with the exception of some feeder fish breeds (after quarantine period).