I haven't done taxes in years, so I might not be the best for giving advice. Here goes what I would want from a client if I was still preparing taxes.
If this is your first year of mystery shopping my best advice is find a good tax preparer. The national chains can be expensive but you can interview your tax preparation expert before you start the process.
The best the thing you can do is set up a spread sheet with everything related to the business. And I mean everything. It's a royal pain for you, but may save you money in the long run. When I worked for a national chain of tax preparation professionals if you came in with a shoe box of receipts, the time I spent going through them was added to your bill. Spreadsheets, would've saved some of my clients big money. Look on IRS.gov, find the Schedule C and it will help you to determine what is allowed and what is not.
Last year my family's CPA allowed me to take the cost of my GPS unit, because my car doesn't have one. She allowed my hotel expenses which were minimal. She made me take my non-business mileage because my income didn't support the business mileage. I also wrote off my membership dues to MSPA.
She was under strict instructions to show the IRS I made a profit. Showing a profit is important. You never ever want the IRS to classify MS as a hobby for you. If the IRS classifies MS as a hobby, you will have to jump through impossible hoops to get your MS reclassified as a business. YMMV, but personally I would rather get the sting of extra $$ so I can always file the schedule C.
This year I'm going to see if my PV500 flies. I also have other expenses I haven't tried in the past.
My best advice is start interviewing people who prepare taxes and can work a Skd, C. If you decide to go with a national chain, try your best to have all your ducks in a row before the 14th of February. The company with the green logo starts raising prices on forms around 2/15 or President's day. 3/15, the prices skyrocket.
I haven't done taxes in years, I may not be the best person giving advice.
Live your life in such a way that when your feet hit the floor in the morning; the devil shudders...And yells OH #%*+! SHE'S AWAKE!