Make a project you need it, help you to do something rapidly, organize for you something, etc....
If you don't know how to do something like that, go to some freelancer websites and figure out what the type of projects clients need and try to do someone on your own.
If didn't write anything in VB.NET
1- Try to code the concepts of OOP (Inheritance\Polymorphism\etc)
2- Try to develop multi-user phonebook (It'd help you know databases and how to link your application to database)