What are the best design patterns, separations or structures which can be applied to ASP.NET MVC web applications?

I would like to know about the different types of desgin pattern/ structure/ speration can be used when developing asp.net mvc application. In this post I will summarize the tecnique used by me to further sperate asp.net application. I would like to know how to improve the current speration tecnique used in my projects. Further, I would like to know if there are any other desgin pattern/ structure or speration which can be applied when developing asp.net MVC applications. The level of speration recomnded to use is to keep the controller as clean as possbile from logical operation and data access layer. The architecture of my projects that I am working with is to call functions in the logical layer from controller. The logical layer classes do all logical operations than call functions in the data access layer. The data access layer then insert, update or return data. Also, I would like to find out if there are any other desgin pattern, sperations, or structure that I should apply to asp.net mvc projects. What are they, when to use them, when to use one over another and what are thier advtages. Further, should we always use desgin patterns, sperations, or structure to make functions reuseable even if these functions called once.