One of the oversights we had came with the Common App. Encourage your son or daughter to read carefully all that is required with the supplements. Some are very basic and just want name, address, phone. Some want three and four additional essays, and if your kid is stressed with APs, ECs, part-time job, college visits, SAT/ACT and lots of other things, they do not need to add more work to the application process.
My husband also said that one should own a house. Do not have stock. We live in an area where it is way too expensive to purchase a home, but we have some stock. Stocks and bonds are wonderful, but they do count against you with FAFSA. No one asks about your home. So your EFC might be higher than you thought it would be.