Gather all of your tax and income information. This means all of your 1099's, W-2s, bank statements, and pay stubs. If you are still considered a dependent of your parents, then you will need their bank statements as well.
Fill out your FAFSA. You can either fill out a paper copy (which is available at your financial aid office) or you can file an electronic copy at the official Department of Education Website. See the Resources section for a link. It is very important that you apply as early in January as possible, as there is a "first come, first served" basis when it comes to Pell Grants. You will be required to input detailed earnings information, including employment history, bank account balances, bills you pay regularly, and any dependents you can claim. You will also need to list your parent(s) information as well if one or both claim you as a dependent, and will need to add their employment/financial information as well.
Wait for your paperwork to process. If you apply in the beginning of January, it may take a few weeks before this occurs. Once received, you should receive an "Estimated Family Contribution," a number that represents how much the government expects your family will be able to contribute to the tuition. If you subtract this number from 100, then that number will be the percentage that the Pell Grant will cover.
Notify your school that you have filed for a Federal Pell Grant. They will be the ones to notify you if you have been approved for a Pell Grant, and it will also tell you how much you have been approved for. Your school will also be receiving the money directly, so it is important to set up an official account with the financial aid office. They should notify you when your funds arrive, and tell you how much of your tuition you will have to pay. Conversely, in the event they send you more money than your actual tuition, your school will issue you a refund check.