When the dealer shows a 5 or 6, the best strategy is to capitalize on their weak position. If your hand totals 12 or higher, it's best to stand, as you're in a relatively safe spot and the dealer is more likely to bust. For totals of 9, 10, or 11, you should double down, as these are strong hands, and the dealer's weak card gives you a good chance to win. If your hand is 8 or lower, you should hit, since you need to improve your hand. Overall, the strategy revolves around standing on strong hands, doubling down on favorable ones, and hitting when you're in a weaker position.