Some signs that a person may have AD/HD are:
Feels restless
Doesn't pay attention to details
Loses or forgets important things
Does not listen to directions clearly
Has trouble waiting for his/her turn
Talks or does physical activity excessively
Fidgets with hands or feet
Blurts out responses at inappropriate times
While some of these symptoms may sound common, a person with AD/HD will have many--if not all--of these symptoms. They will also last for over six months and create a disruptive environment (e.g. you can't get your homework done because you can't concentrate).