We really can't give you specifics. We don't know you, your abilities, or your interests. We could literally make hundreds of suggestions but all it is is an exercise in futility, and they are of no value, if they don't suit your interests and/or abilities.
You say you "got the qualification", so you must have some sort of education. Take your assignments from your programming classes and experiment with expanding/improving them.
Is there a situation that you think could benefit from using a computer? Write a piece of software to provide that benefit. Is there a piece of software that you're familiar with? Find a way to make a better version of it (being mindful of copyrights of course).
I Developed application in C# with crystal reports and created setup file in third party (Advance) Installer.When i installed my application on client system application is working but ...