Many students have not accrued much credit before they attend college. Building credit takes time. Some tips on accruing credit include:
Apply for a credit card and pay your bill in full every month. If you have trouble being approved for a credit card due to lack of credit history, you may want to consider getting a secured credit card or becoming an authorized user on an existing account of a friend or family member.
Apply for a credit limit increase to improve your credit utilization ratio
Work on paying down any outstanding loans, including auto loans, student loans, and mortgages, as that will contribute to your credit score
Contact the credit reporting agencies to have your monthly bills, such as phone bills or rent, added to your credit report
Make on-time payments to maintain a favorable credit score