What are some Performance [Dos/Don'ts] in C# -ASP.NET

Question

I am finalizing one of my projects and taking a look over the whole project looking for mistakes, bugs and performance mistakes. I am using MVC. I caught one Don't and that is:

Never put a RenderPartial within a loop. it will drastically slow down your whole server.

Answer 1

Never store a WebControl to Session.

Because it has a reference to the Page object, it ends up storing every control to session.