SDK development for my application

Look out for what you would like the programmer that uses your application to be able to control and manipulate. Think of yourself as a user, and look out for the functionalities that you might like to see. This must give you a rough idea of what needs to be exposed off your application through the SDK.

Then try and group those features that you'd like to expose. Let me assume that your application does secure compression of files and folders.

So now for example, one group of functions might deal with the way your application would deal with data security (encryption, decryption, the algorithms that you'd let the programmer use to do them, provision for a password, etc.,).

While another group of functions would deal with how the compression itself is done (provide the programmer with ways to decide upon the output format, should it run on the background, etc.,), operation mode (heavy or light - how many threads to use to do the operation), etc.,

There are gotchas to take care of - plan the function calls very carefully (think of the prototype, the arguments, see if you need to keep something reserved for future use, think of if you'll need to provide backwards compatibility in the future, scalability, etc.,).

I could go on, but I believe that you might have already got an idea (on how to start) by now.

PS: Kindly use the message board at the bottom of this page to discuss anything related to the query or any answers given.