By the time a child is about 6 years old, all of their basic motor skills, both gross and fine, are fully developed. They spend the remaining years of childhood refining those skills and achieving greater coordination.
Before children can develop fine motor skills, they must have three fundamental abilities. Stability governs balance and movement; it allows a person to keep one part of the body motionless while moving other parts of the body independently. Bilateral coordination refers to the ability to use both hands, with one hand working and the other helping. Sensation is the understanding of what body parts are doing. Once these three abilities are established, the child can begin to develop dexterity --- the small, precise movements required for fine-motor skills like tying shoes and writing.
By the time a child is 8 years hold, he should be able to perform many fine motor skills on his own. He may still have some difficulty or lack of refinement in his execution of these skills, but the basic ability should be evident. Tasks include buttoning and zipping, eating with utensils, using writing implements, cutting and pasting, stacking blocks, and catching, kicking and throwing a ball.
All children develop at different rates, and it is not uncommon to find a child who is advanced in one skill set and slightly behind his peers in another skill set. Parents or caregivers who are concerned about their child's motor skill development should seek advice from their child's pediatrician or from a child development specialist.