How can I help my child who is 15 months and not walking yet?

Be patient. The cdc recommends getting an evaluation if a child is not walking at 18 mos. Of age. I would suggest giving your child a bit more time before worrying. Remember that while there are some definite problems, most kids simply develop at their own pace (which has little to do with how they end up). You can always discuss it with your child's doctor or nurse practitioner if you are still worried.