Very good question and now is the time to get this going.
I usually create a spreadsheet that has the following information on it:
- income per month
- groceries per month
- activities per month
- cable, internet, phone, utilities per month
- gas and kilometers driven per month
- mortgage or rent payments
- insurance
- advertising costs
- anything else you had to pay for to run your business
make sure you have receipts to back up your claims.
I took this to H&R Block, they seemed to do a fine job. It's a pretty simple business so you shouldn't have to be paying more that a few hundred dollars for someone to do your taxes (you shouldn't need an accountant to do this and pay $1000s!).
Hope this helps.