I started with a spreadsheet and now I use Outright.com. They have a free version or you can pay for their premium version so you can have tax info. I had the following headers for my columns "date (sold), paid, shipping, item (description), notes, Etsy fee, DC fee, PayPal fee, total" I made formulas to calculate the fees and add up the total. I had to keep going back and tweek it. That should give you a good start though.
I have a different one for expenses. But like I said, I'm not using it anymore. I like how Outright automatically imports everything from paypal and etsy. I manually enter expenses.