Teach kids to play Uno and Concentration. Uno teaches kids to pay attention to the cards in front of them and play the ones corresponding with those being overturned. Concentration is a card game in which every card is face down and players go through a process of turning them over to create matches. It teaches concentration because players have to stay focused and remember the location of cards that have already been overturned.
Active listening teaches kids to focus on what's being said or they will miss valuable information being given. Before reading to kids, ask them questions about themes or topics covered in the reading to prep them for what they are about to hear. Ask them a list of specific comprehension questions from the reading and see if any recognized the answers to those questions as you are reading.
Playing missing numbers games teach kids to stay focused. You start counting numbers and periodically leave out a number, expecting the child to fill in the missing number soon after it is omitted. Also, having kids recite tongue twisters like "she sells seashells by the seashore" help them improve concentration because they have to remember the phrases word for word.
The process of completing a puzzle teaches children to stay stationary for moderate to long periods of time trying to complete a given task. Floor tile, jigsaw and connect-the-dots puzzles help kids improve their attention to detail. The connect-the-dots puzzles especially help kids stay focused on the direction the puzzle is taking. Without following the proper direction, the puzzle will not be completed correctly.