Your business model is basically how you've designed your business, focusing on how you will generate revenues/income. Many sellers both here and in all forms of business amazingly enough don't put much thought into their business model. They just takes some products and attempt to sell them and make a few bucks. But for something to work long-term you have to put real thought into it. Are you able to purchase stuff for resale at a price that allows you to make enough profit to cover costs involved in the operations and to have enough left over to make the effort worth it (profit margin)? Are the products you're attempting to sell actually selling (demand)? If so are enough selling to make the wheel go (volume)? Is what you're selling have long-term demand or are we talking about fad items or stuff that could become obsolete in the near future? Is your stuff unique enough that you won't get lost in the mass of competition?
These are some of the hard questions that we all need to constantly be asking ourselves if we want current and continued success. We have to be able to be honest with ourselves and admit when our business model is just not working. In today's world you have to embrace change, as uncomfortable as that may be, and tweak, evolve or completely revamp our business models when the need arises or ideally BEFORE the need arises. Personally our philosophy is that you need to have a good balance between specialization AND diversification. That sounds kinda contradictory but it really isn't. We feel you have to focus on an area with the goal of becoming the best at it...but you also always have to be looking to add things to what you sell that compliment what you already do without going in a completely different direction. This way you are always building new legs to stand on and thereby less vulnerable. If you put your mind to it, it is even very possible to "season proof" your business. The summer being slow in our opinion is in many ways a myth. I've lived in Florida, in the summer most people there are indoors beating the heat and are spending as much time online shopping as anytime of the year. I'm sure it's the same way in many hot climates or anywhere that the dead heat of summer forces people indoors to the comfort of AC. If however all you sell is ice skates well then its gonna be slow in the summer...but if you added roller blades to your line??...A very raw example but I think you get my drift.
Staying on your toes is obviously very challenging both mentally and financially. But it's what you have to do in today's world to succeed. It would be nice if we all could just get a few easy to find products, list them and then pocket the easy money. But let's face it that isn't realistic. When the bottom line is just not adding up there's no point blaming ebay (as frustrating as they can be) because even if they aren't what we'd like them to be, if you can't make a buck here with your model, you probably won't make it anywhere. With all its faults, ebay is still a dirt cheap way to do business.