将实时Web应用程序移动到新服务器的最佳实践？

I am tasked with moving quite a few web apps including the databases to new servers, they are ASP.NET. I was not the one to create and setup these originally so I must try to figure out what exactly I need to replicate in order to not break anything and so the customers have no idea that anything was moved. I am tasked with moving quite a few web apps in