L’olivier est immortel; la seule façon de le tuer est de le noyer – François Boutroux
The most important thing is good drainage: The olive tree grows best on slopes when the water runs thru them.
The soil should not hold water, like clay.
If potted, the water needs to be able to drain through the holes at the bottom of the pot.
Potted trees need to be watered more often than trees planted in the ground; you can use any water to water them. 
The olive tree likes alkaline soil and strives in limestone but it needs the minerals that can be found in potting soil.

Unpacking and caring for your olive tree when you receive it, with Jay

Long term care of your olive tree so it stays alive, with Will and Corine

Repot your olive tree, with Corine

Olive trees look beautiful in nearly any environment - planted or potted.