Shochu traditionally has been served in a number of ways. Originally they were uncomplicated and cheap keeping their focus on accentuating the flavours present in each variety of the spirit and making it more easily drinkable.
Originally it was served with water, hot or cold, added to it. Either this or with the addition of green tea were most likely the original ways in which it was drunk.
As mentioned before the ABV of shochu can be up to 40% which may have led people to weaken it with whatever was at hand i.e tea or water itself.
Ice is of course an obvious choice and one that has been used more in recent times, both to water down the drink and affect the temperature and thus the flavour.
In recent years and since Shochu has made it's way across from Asia to the western world we have seen more and more adventurous and original flavours being used to compliment the different kinds of shochu.
New and popular flavours include strawberry, peach, rhubarb, ginger, and white tea. With the ongoing growth of the spirit and explosion of new and interesting base products each brand is seemingly gaining a flavour profile of it's own which means there are constantly new combinations being thought up.
Even more comtemporary serves, and perhaps at the opposite end of the creative spectrum, include pre-made canned shochu "cocktails"