In Blackjack, you should always split Aces and 8s because they give you the best chance to improve your hand. Splitting Aces can result in two strong hands, and splitting 8s turns a weak hand (16) into a potentially better one. Avoid splitting 10s or face cards, as they form a strong total of 20, and splitting them would likely weaken your position. You should also split lower pairs like 2s, 3s, 6s, and 7s when the dealer shows a weak hand, typically between 2 and 6, as this increases your chances of winning. Finally, splitting 9s is beneficial when the dealer shows a weak hand (2-6 or 8-9). These basic strategies help improve your chances of success in the game.