Left Foot Strategy
A consistently good move when you don’t have a better clear choice is to aim for an opponent’s left foot. If your opponents haven’t left a space wide open, aren’t both back at the baseline, or aren’t otherwise out of position, one of the best things you can do is drop that ball directly at a left foot. It might be considered more of a defensive move than offensive, although sometimes they won’t be able to return it. In most cases, they’ll return it badly, so you might think of it as a two-part strategy. The first shot is aimed at someone’s foot. That someone will return it badly, and you can then put it away.
Of course this assumes your opponent is one of the 89% of players who are right-handed.
Ideally, you’ll take a moment before the rally to notice whether your opponents are right-handed, left-handed, or ambidextrous, and if your opponent is left-handed, you aim to the right foot. But if you don’t remember or didn’t check, a ball placed to the player’s strong side, as long as it goes to a foot, will generally work well anyway.