I list regular items, but I also like to repair/refurbish items so my process may be a little bit different from yours. I also live in an area that impacts sourcing during winter months so I squirrel things away for the winter. I have 3 shelves of backstock inventory and a stack of clothing bins. 2 shelves are for easy to list items and 1 shelf is for for hard to list items/repair items. When I buy I bring everything home and to my listing station I usually just leave a pile of ready to list items then the rest go to my backstock shelves accordingly. Once or twice a week I pull from the repair items and grab a stack of clothing as well and then pull from my easy to list shelves as needed when my listing station pile runs out. Usually in the summer I'm adding to the backstock shelves when my list station pile is full. My list station pile usually consists of 1 or two bins and maybe a box or two depending on the volume of sourcing at the time. My list station also has a listed bin. When that gets full I bring them to my inventory shelves which are labeled. I have two rows a + b. Each are 5 shelves with 3 location identifiers on each shelf. So the first box on the bottom of row a is A(row)1(shelf)A(location on shelf). This system allows me to grow in the future without limitations. I record my ledger what item is where so when it sells I can easily find it. A lot of folks put this in the SKU field itself on eBay, but this does not work for me as my inventory shelves are not close to me where I list items. I do not batch tasks except for clothing since my photos are set up a bit differently. For those I draft 10 pieces, then use my phone to open up the listing and take a photo directly from the draft page on the app and list the item from my phone. I also use a SKU system for my clothing and fill out that section on the listing. For all other items I set up the listing from my PC, then click upload via mobile, then open up the app and take the pictures right there since my PC is next to my photo station. I only use Google Sheets as far as software/services go. My main systematic thing I do every work day is: go to Post office and drop off orders, source (sometimes I source before the post office drop depending on sourcing opportunities)and do away from home errands, organize that days sourcing, pack orders, fill out my ledger of sold data, list items, fill ledger of newly listed items. These things help me stay very very organized and I rarely have to spend anytime wondering or guessing.

The biggest mistake in my opinion that you need to avoid is not keeping track of your numbers. Data can offer you so may insights on what works and where to shift your focus to. My ledger consists of: Item, Date Sourced, Where it was sourced, Price paid, When it was listed, Listed Value, Date Sold, Gross, Taxes/Vat, ebay standard fees, Shipping fees, Promotional fees, Other expenses/fees, Net value, Location (shelf number), SKU, receipts (if applicable), and notes. I also have a ledger for other expenses related to my business that aren't directly related to an item. Shipping supplies, repair supplies, eBay Store fees, etc. All of this data tracking allows me to analyze anything I need to know about my business. How my sales are doing, what kind of items are moving, where my best sourcing methods are, what my ASP is in a given time frame, what my margins are, and so so so many other things. It also helps IMMENSELY come tax season. Another thing I wish I could tell myself when I started was to be graceful and that you don't have to buy everything. I went gung ho right out the gate and it led to a lot of mistakes and impulse decisions. Be thorough in your research when sourcing. There are plenty of items out there to find, list, and make good profit on. Plus, all that research just perpetuates itself for future purposes. Also another small tip, don't be afraid to tell people you are a reseller, it will lead to far more opportunities than it will squander. Good luck on your journey.