Missing References for new Project

When you start a new Xamarin Forms project using Visual Studio, you often see a bunch of errors regarding missing dependencies. You might see something like:

Error CS0246: The type or namespace name 'Xamarin' could not be found (are you missing a using directive or an assembly reference?) (CS0246)

There are a few things you can do to quickly resolve this issue:
1. Right click on Solution and select Rebuild Solution.
2. Close the project, and re-open it.
3. Go to Package Manager Console and attempt to update the dependencies.
4. Manually add the missing dependencies by right clicking on References and selecting Add References in the Solution Explorer.