Open a wireless phone account. Some wireless carriers will open accounts for customers as young as 16. It’s important to read the user agreement carefully to make sure there are no long-term commitments that may be undesirable. But provided that the payments are made on time, this information is reported to the credit bureaus and helps improve the minor’s credit score. Late payments, of course, have the opposite effect, so it’s important to have a plan that your son can keep up with.