One of things I do is encourage the student to take an art class at a local college (some schools offer Saturday classes to high schoolers), especially a life drawing class. Sometimes students don't 'believe' me when I tell them that colleges are looking for work from observation. I have them go to portfolio days with their work and show it to a recruiter.(usually their JUNIOR year, so they have time to get a portfolio together) The recruiters tell them essentially to go home and redo their portfolios from observation. Those students always come back to me and say that I was right, and would I help them get a portfolio together. Assignments such as "open your closet door and draw what you see" or "open your junk drawer and draw what you see" are good start.