Class library are a bit harder to debug compared to dialog based or command line based application. After deciding to use NUnit I was using a dialog based application to instentiate my class library debugging, however there is a much easier way of doing that
1) Create class library with unit tests
2) Take properties of the class project in visual studio, and select the debug tab. properties -> debug
3) Set Start external program to C:\Program Files\NUnit 2.4.1\bin\nunit.exe or whereever you nunit executable is placed.
4) Set the test library as startup project.
5) Start debugging the project, it will bring up the nunit test application, if there are breakpoints in the application it will break into it.
Styling Sharepoint sites depends heavily on creating and editing XML files that need to follow sharepoint schema.
the first thing to note is if WSS (Windows Sharepoint Services) are installed on the same machine as you Visual Studio on not, Microsoft suggests to develop Sharepoint application on a windows server 2003, so that debugging and testing is facilitated.
If Visual Studio is on the WSS machine then all you need to do is create a xml file e.g sharepoint.xml in the folder Program Files\Microsoft Visual Studio 9.0\Xml\Schemas
Place the following code in it
<Schema href="%CommonProgramFiles%/Microsoft Shared/web server extensions/12/TEMPLATE/XML/wss.xsd" targetNamespace="http://schemas.microsoft.com/sharepoint/" />
Restart Visual Studio and add the following line to your top most element xmlns="http://schemas.microsoft.com/sharepoint/" in your XML file this should enable intellisense in your XML file.
For Environments where WSS is not installed on the same machine, wss.xsd file can be copied to the development machine and the above code altered to point to the xsd file location.