Running a business isn't easy and you can't just run it whatever way you like. When you run a business you should make a Business Plan because it is the way to keep track of your goals and the best path to follow.
A business must be run not only by the day but by the year or years to come. A Business Plan can't be a fixed orientation but rather a dynamic orientation that changes with the state of the economy and customers trends.
If you don't do a Business Plan you might get lost along the way and you might not be able to accomplish your goals. Some goals are hard to reach and might become impossible to reach if you don't have a realistic and effective Business Plan.
You can find the best way to Plan Business over the internet but you must keep in mind that it has to be dynamic, it even depends on the life cycle of each product you sell. Some products lose their interest and are put aside as new product come to replace them, that's the downfall of that product life cycle and you need to adjust the way you do Business planning so that you don't invest any more in that product and that you make the maximum profit as possible from the units you already have in the shop. It takes a lot to Plan Business and you have to be always watching out for market changes because they determine the money you can make with your products.