The more difficult task is coming up with an item to sell!
When you are in the decisional process of “what to develop?”, you should start thinking about creating scripts that other mobile developers would have a hard time implementing themselves.
Something that cuts the development time and cost of other coders/designers.
You can also read some forums about mobile development and take note of the developers need in posts like this “Pls help me. I don’t know how to code ….”.
Just trying to make your items suitable for someone with little programming knowledge will help in boost your sale.