I am an accountant. I have many people who can never find all of the inmortant paper work come tax time.
Get either a expandable folder that has 12 slots or manilla envelopes for each month. Place all of your tax deductable receipts in the month they were bought.
Also include all of your Dr's appoinments, receipts and mileage. Medication receipts and mileage. If you tally th milage up once a month is takes less than 5 minutes.
Make sure to note any and all volenteer milage and donations. If you donate clothing, and HHG list exactly what you gave. ETC