A strategy for “Uno” is to discard higher-numbered cards first, unless the player has many same-colored cards. For instance, if a blue 8 is on the table but a player has one red 8 and several blue cards, he should play one of the blue cards.
When a player has a lot of the same-colored cards in his hand, he needs to focus on playing as many of those before another player switches the color. The player always has to assume that the color is likely to change before it's his turn again to play more cards.
Players also need to focus on getting rid of the Draw Four wild cards as quickly as possible. Players can only use these cards when they don't have any other number or color cards to play. This can make getting rid of the Draw Four cards difficult. Also, if the player is holding a Draw Four card at the end of a round, it costs him 50 points.
While players should get rid of the Draw Four cards, they should hang onto the wild cards as long as possible. This card doesn't require the other player to draw any cards, but it's playable whenever the player needs it. If the player has the option to play a wild card or a normal card, he should always choose to play the normal card and save the wild card.