The .NET development landscape is awash with some fantastic tools. Visual Studio itself includes a wide range of powerful tools but there are some great free and commercial third-party tools available, including some from Microsoft themselves. One I added...
One of the things I always do when I start a new C# project is turn on Code Analysis for the project and set all of the rules to return errors rather than warnings. This might seem rather draconian but once you get used to the rules it's fairly straightforward...