I've written some articles that summarize what I usually tell patients when asked about these common pediatric issues. If I don't have a description here that you can use for advice, I recommend the "Kid Care" app (free!) by St. Louis Children's Hospital for a reliable source of helpful advice on common childhood symptoms. If your child's symptoms don't resolve with following the advice given, then it's time for a doctor's appointment.
We welcome ideas on other issues that you would suggest might benefit from having an article written!