First and foremost, trust your parental instincts. Secondly, talk to your doctor about any concerns that you may have and/or consider have your child screened by a pediatric occupational or physical therapist. He/she may be able to provide you with some simple activities to promote development and the acquisition of motor milestones.
Therapy can begin in infancy, and common signs to look for are children having difficulty eating or sleeping or acquiring developmental milestones like rolling over, tracking an object visually or bringing their hands to midline.
As your child gets older, therapy may be indicated if he or she has difficulty with self care skills or keeping up with others on the playground or at the park. An occupational therapist can help children dealing with self regulation issues, frequent tantrums and those who have difficulty calming.
The sensory integration checklist at www.touchstonekids.com can help determine if an occupational therapy evaluation could be beneficial for your child.