Best practice and proper class design in object oriented language

Dear All,

As many folks know that anyone can write a working application after a few months trainning, but not everyone can write a nice and robust application in such short time of period, and in fact many programmers who had a few years experience still can't perform a best practice class design, and unfornaturely, i am one of those poor people.

I read through this link: http://msdn.microsoft.com/en-us/library/ms229042.aspx, but it is just theory and no practical examples there, what I really need is a example that can demonstrate those guidelines or principles.

I had googled the internet, but most of the post there are just theory. Can someone in here supply an example that addresses the good object oriented class design or point me to the right place that has such examples (preferable in c#).

Many thanks.