Summarize this article in one sentence.
Make a mental note of each card that is played. This may take some practice, but the more attention you pay to the game, the better your focus will be.  Doing this will give you an advantage over the other players. By counting cards, you can learn to predict the moves of other players. While paying attention to the cards, if you notice 1 player using many of the same color, such as green, use a card to throw them off track. You can use a card with the same number but with a different color, for instance. For example, if 1 player plays a green 7, play a blue 7. This changes the suit from green to blue. For example, if you notice 1 player has no yellow cards, keep the suit yellow as long as you can. You can maintain the suit by using yellow cards if you have them. This gets rid of your cards while making them draw additional cards.

Summary:
Pay attention to every card that is played. Play a different color if a player uses many of the same colored cards. Use many of the same color if another player continues to draw cards.