Unfortunately, you do not always get taxes back (refund) after filing them.  Your tax is figured like this:

• Total of all your income items - some adjustments = adjusted gross income
• Adjusted gross income - your personal exemption. Note: If you are someone's dependent than your exemption is 0.
• Then - your standard/itemized deductions (standard for most people including students) = Taxable Income
• + some credits and - other taxes if applicable = your total tax owed
• total tax is compared with taxes withheld on your W-2 and other forms
• If too much taxes were withheld, you get a refund. If too little were withheld your owe more taxes.