Well olive trees love water but they don't like wet feet.
Starting now until september you can give 60 liters of water every other day. It is to late for pruning, well actually you an prun anytime but then you loose the olives. Basically prune after you pick. The leaves live for 3 years so about now you should be seeing a few yellow leaves, which is normal. Here is something important, the trees dormant times are August and January which si when you fertilize, don't over fertilize. In August the trees have olives but then you see the leaves kind of cul an you think there is a problem, there really isn't they jsut take kind of a summer break.
You won't have enough olives to make oil so you would hand pick your olives in September for table olives, give a little squeeze and they should give jsut a little bit and they are ready to pick. Are there a lot of olive trees in your area? If so you will need to control for the olive fly. If no other trees dont' worry about it. We ahve two insects we control but I only know their French names. Best is to search at U.C. davis extension there is a ton of information on the pests you may encounter.
Here is the recipie for making table olives. Get some wood crates like what fruit and vegetables are delivered in to grocery stores. thow in some wood shavings or wood excelcior. Get rough salt, I like sea salt but it really doesn't matter. Pout about 1/2 box of salt on top of he wood shavings. Place raw olives on top. Pour oh about another 1/4 to 1/3 of a box of salt on top of the olives. Put outside under the olive trees. Every once in a while go out there and shake the olives around a bit. If they are really leaky a lot, change out the shavings. Wait about 6 weeks, bring in house, eat olives. You can keep them in a canning jar with oil and it does not have to be olive oil, of course in USA even if it is marked olive oil who knows if it really is or not.
Here is another kind of neat trick. Pick olives put in jar screw on cap. They will stay green for one or two years. As son as you unscrew the cap they will turn black. Our neighbor showed us this and I don't believe he uses salt either. For really good table olives you might try the Fench variety of tree the Salonenque. The origin of that tree is my city Salon de Provence.
Oh don't let your trees get to tall, you want to be able to pick the olives. If you let it get to tall the olives grow on the top and not the bottom and you can't pick them. Prun your tree like any fruit tree, you cut out the inside, like a cup shape.
Olive trees can live really well without taking much care of them. Of course if you don't water the olives will be small but still you will get olives. Think of an olive tree as an evergreen, it is green all the time.