How to avoid memory leakage in VB.Net windows application?

Question

Dear all,

            I am creating a windows application using vb.net.The issue is while running the application,  the memory usage at the Windows Task Manager keeps increasing for the application even without any activity and minimizing the application,memory decrease automatically.How to avoid leakage of memory?
            Some peoples recommending to use IDisposable Interface  to release unmanaged resources.But i don't know how to use  IDisposable Interface in VB.Net windows application.
Please help me.

With regards,
Fuad