Your olive tree will require regular watering, but take note – it will not cope with being overwatered! So, once the soil has dried out (to about 5cm deep), give it a light water. There's no need to spritz the plant between watering either as it's used to dry climates.
If you really want to give your olive tree some TLC, give it a "bath" every few months, ensuring you're washing its leaves to rid it of any pests that may have taken refuge under the leaves.
Olive trees need to be planted in a large container with plenty of holes for drainage – ensure the root balls have plenty of room to expand, or you'll find yourself repotting much sooner than you'd like. Filling the pot with gravel or similar filler at the bottom will help keep the soil well-drained. Given their love of dry climates, a cactus potting mix works well for olive trees.
Generally speaking, olive trees need a fertiliser with high source nutrients, particularly nitrogen. Use a solution that is balanced in nitrogen, phosphorous and potassium and fertilise your tree in early spring and late summer.
As well as needing plenty of sunshine, it's important to note that olive trees can grow quite large, so consider choosing a dwarf variety, which tend to get to around 1.8 metres. Keep in mind that once your olive tree grows larger, it may eventually need to be moved outside permanently, but you should still be able to get a good few years of potted life out of your tree.