1) ENCOURAGE (not TELL or ASK) kid try his/her very best to do well with HIS/HER best possible GRADE
2) CONCENTRATE ON studies: GPA is the key
3) CONTINUE to take the Honors/AP courses s/he is able to handle with at least a grade of B at Junior and Senior Years
4) Again Encourage s/he well prepare ACT or SAT for a resonable good score
5) Get alone with School Counselor and teachers as an enthusiastic learner and a good citizen in school and community
6) Help kid pay more attentions on the career path being suitable for him/her
GOOD LUCK. Keep in mind: Most of kids are the average one, they will be fine.