You know what, I'm seriously curious about this as well, not because I have a similar income method to you, but because there's expenses in a business, and sometimes if you don't get tax breaks by showing your expenditures, then you'll be LOSING money by the amount the government requires you to pay, because you didn't bother to show your expenses to even make that money in the first place...
I don't have a firm grasp on HOW to go about getting the appropriate tax breaks and showing your expenses to even make the money that you've made, but if nobody here helps, I'd advise going to your bank and talking to an accountant, and they can probably help. If nobody here speaks up, then that's definitely what I'll be doing... actually, I'll probably be doing that anyway.
Something you will NEED to do is keep the receipts and proof of expenses, because that's how you'll prove to the IRS you're not making up figures. It doesn't seem they mind too much when it comes to reporting tax breaks work just a few hundred dollars, but when you're busting out $20,000 or so, they're definitely going to want you to prove expenses before they'll give you a break.
One other thing, I don't know for sure, but as long as you keep your receipts of business expenses around, I'd imagine that somebody from HR Block or some similar agency would be able to coach you on what they'd need from you to accurately report your true earnings and expenses to the IRS... but that's just hypothetical.
I hope I helped you out a little.
