Sometime Project have included many thing with a project.suppose a ASP.NET MVC project maybe included Test project for the project you run or have some more project who attach to the current project. it's take a long time while project is going to debug the reason for that is because project have many subproject or attached project then compilation of all maybe goes long. the solution is that build and debug current project instead of all. it's same time on compilation in Visual studio. for configure build only current project you need to configure it in Visual studio. 
click on the button and select Configuration manager choose the project who you currently worked and unchecked all other. After that Visual studio debugging goes faster.