Beginner
Start children on jigsaw puzzles at an early age. Wooden puzzles usually come with large pieces, and the background is on the puzzle. They usually have a small number of large pieces that are easier for young children to grip. When the puzzle is completed, the child can dump the pieces out and start again. These puzzles come in an assortment of pictures such as animals, cars, trucks, characters from shows and flowers. This helps children learn about their environment as well as improve their motor skills.
Intermediate
Once children learn how to put jigsaw puzzles together, they can advance to puzzles that don't have the backgrounds on them. These come in a box, and you have to match the pieces to the picture on the box. These pieces lock together when you find the right one to connect. Don't buy puzzles that are too hard for their age group; if children feel overwhelmed, they may lose interest. Check for appropriate ages on the puzzle. If a child has been doing puzzles for a while, he may be able to handle ones that are for a higher age group.
Advanced
By the time children reach the age of 9 or 10, they are usually ready to work on harder puzzles. Work with them on these puzzles so that they don't lose total interest. Teach them to put the border together first and then work on the rest of the puzzle. Help them to compare the colors and see where each of the pieces may fit. It's easier to impart this knowledge if you work with them, but don't hog the puzzle--let them work it mostly on their own unless they want to work with you as a bonding experience.
Online
Puzzles are also available on the Internet. Check out some of these to see whether they are the appropriate age for your children and that they are safe, as in virus-free. These online puzzles teach different skills, such as learning to use the mouse. However, don't forget to have an antivirus program to protect your computer.