I would take your tax returns to a tax agent -the charge is about $100 and tax deductible . Get them to do return and check what deductions you could be eligible for. If you are the sole earner in a family of four sounds as though you should be keeping records of all out of pocket medical expenses( dentist ,doctor, prescriptions,etc) as over a certain amount they are eligible for a deduction, and if your children are school age some of these costs can be tax deductible . A tax agent will give help and should be able to assist if you made any errors on previous returns and will give you an idea of what to look for if you file your own return in the future.