Inconsistent data : This becomes most apparent when trying to find a particular record or cell, based on the contents. If a space is incorrectly added in the wrong place, the search or filter fails.
You'll need to include more than a basic level of development and calculation in your spreadsheet. There are lots of free spreadsheets on the web. Most of which are very simple and easy to build. People aren't going to buy a spreadsheet that they can get for free. Take yours to the next level by adding all the value you can imagine. Then research on how you can offer a little bit more on the development and functionality side.
All of these things pull you away from the thing you really want to do...which is to build and sell great spreadsheets. The best thing to do is use Excelville.com since they have web developers and internet marketing specialists to help get exposure for your spreadsheet.
The mentioned package includes valuable programmed spreadsheets such as the "Income and Residual Tracker" - provides professionals in the entertainment branch with detailed information regular and residual income; "The Biorhythm Plotter" - helps users in planning various events and actions based on Primary and Secondary Biorhythms (the spreadsheet solution allows users to choose the right timing for their actions according to personal intellectual, psychological and physiological factors); "Basic Actor Package" - designed to facilitate the process of calculating expenses.