To build on Josh’s points. ( I quoted the wrong post 
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1 and 2- Get comfortable with creating spread sheets. When I pick up a lot, I immediately begin inputting them into a spread sheet that includes Holo/Reverse Holo, Name, Set#, Set, Ebay sold Price, PSA 10 price (if available). At the bottom i have a formula in place (SUM), that adds up the total value and total amount of cards. With that data I can quickly see what I need to do in order to create Listings for Lots, Single card listings, etc. Once the spread sheet/book is made it all becomes copy and paste, so your hours are front loaded in a sense. And I wont post any listing until every card is “inventoried”. What this allows me to do is keep track of the market in a sense, I can see what I originally quoted these items at, if they have grown in value or decreased in value, etc. almost lets me feel the heartbeat of the market for that genre of cards.
In regards to his comment on volume, just be mindful of what it is and the condition. Like I said earlier, I picked up a lot of 2400+ cards last week (Ex-Current), which only about 250 were holo/reverse holo cards, the rest were bulk commons. But as of today, I have less than 100 left to move. Have a game plan on what you are going to do with the lot before you buy it, don’t just buy a lot and not know what you want to do. I knew that with the BULK, I was gonna comb it for a mistake by the seller (which I found a Team Rocket Returns Dark Gyarados) and once I was done with it I was gonna ship the rest of the bulk to a bulk buyer. Then the rest of the Holos/Reverse-Holos were gonna get sorted by set and sold as lots.
In regards to #3, I agree. These last 100 cards may never move. Luckily, between the bulk and what I have moved on Ebay, i have covered the initial investment.
#4 is probably the most important part. I messaged my first customer (be bought a $20 lot) and told him that I just dropped his item off at the post office and I greatly appreciated his business." Literally, 30 mins later, he bought another 4 lots from my store. Would he have done so if i hadn’t reached out, who knows.