Creating a Web Part
As mentioned previously, Web Parts use the ASP.NET infrastructure. Therefore, if you have ASP programming skills, learning and using the Web Part interfaces, attributes, and development models will be a straightforward prospect.
Every time you have to implement a new Web Part, begin with documenting its functional requirements and overall high-level design. Decide the properties that your part will expose, the interfaces that need to be implemented, the operations the Web Part will need to handle, the necessary security rights it will need, and the deployment scenarios it will require. If you have the option, always try to focus on the security and performance of the Web Part as a top priority.
As an example for this section, ...