The ideal poker strategy to win the most showdowns is to CallEveryBet.
If you have 52o, flop KQ2, and the turn and river both come down as deuces, you will almost certainly win, but ONLY if you hang in there with deuces / crap kicker to see it. No expert would pay good money to continue with such a hand, but it is the way to get the most wins in your column. Of course, this happens to also be the best strategy to lose as many showdowns as possible. You've got to be in it to win it, and also to lose it.
Compare to the AlwaysRaise strategy, which actually wins more hands.