Challenge: When you’ve created an application, you tend to forget this fundamental syntax as well as other concept such as Pattern. Solution: Some useful of OO Concept and Pattern: 1. Abstract Class VS Interface – http://www.codeproject.com/KB/cs/abstractsvsinterfaces.aspx 2. Design Patterns in C#/VB.NET – http://www.dofactory.com/Patterns/Patterns.aspx 3. Strategy Pattern in C# – http://www.primaryobjects.com/CMS/Article70.aspx