Although it might seem simple, toddlers must first learn how to grasp objects before they learn to color. Learning to use her index finger and thumb in a pincer grasp is an important pre-writing skill. Allow children to have lots of practice picking up small objects, such as crayons, and holding them in their hands. Most toddlers will hold a crayon in their fist when they first begin coloring. This is normal, and as their fine motor skills develop, so will their grasp.
Once your child is able to pick up a crayon and hold it in his hand, show him what it can do. Using your own piece of paper and crayon, show him how to make long sweeping lines and other marks on the paper. Do not grasp your toddler's hand; rather, allow him to move his own crayon in whatever way he is comfortable with. Praise any efforts he makes to put marks on the page. Talk to him while he is doing this, being sure to point out that he is making the marks on the paper by himself.
Children gain the ability to make long sweeping lines before they are able to make smaller, circular marks. Most children will do this by moving their whole arm across a sheet of paper rather than just their wrist. Children will hold crayons in their fisted hand and sweep their arms over the paper, creating lines or arcs. Give children plenty of opportunities to practice using their small muscles and discover different colors while coloring with crayons or markers.
Sometime during the toddler years, before a child turns 3, she probably will begin to show an interest in the printed word. If you find yourself writing a grocery list or making out a check, your child might ask to see what you're doing. Many children will attempt to imitate the patterns of adult writing by making small marks on the paper that go from left to right and start at the top of the paper and go down. Most of the scribbles your child makes at this stage have the same characteristics of print. This is an essential step in learning how to read and write and should be taken as a sign that your child is developing normally.