It depends on what you want?
For star trails you'll want lots of 30 second exposures, turn off long exposure noise reduction, then use Statstax or similar to stack.
For milky way shots you'll want a wide angle and high ISO and one shot.
For the moon remember it is very bright, if you want detail in it then spot meter the moon itself or you'll blow it out.
In any case you'll want a sturdy tripod and cable release.
Let us know what you want to achieve and we'll be able to give more specific information on how to get there.