Can you appeal for more financial aid? If so, how?
You need to contact your financial aid office and ask them to package you to the maximum financial aid allowed. Most schools do this already. Once you complete your FAFSA, a budget is determined for you by your school. You cannot receive financial aid awards in excess of your total budget.
If your goal is to minimize the amount of debt you are in then I would not request to maximize you federal aid package. This means that they will create you financial aid package to include the maximum amount of loans you are allowed to borrow and actually increase your debt.
In some very unique and specific situations, a student can do what is called a professional judgement to either be considered as independent and file without your parent's income, or for less income to factored into your eligibility.
Again, this only happens under rare circumstances, so you would have to talk to someone in your school's financial aid department to see if you meet the requirements to file a professional judgement. Good luck!