If you are said to improve .NET code performance what will you do ?

These kind of questions are very generic. Just pick up 5 best tips you know our have implemented and say it before the interviewer. Below goes my 5

• Use stringbuilder as compared to normal string concatenation.
  
• Use stored procedure rather than inline sql code.
  
• Use caching for  frequently used data.
  
• Use generics collection as compared to simple collection , to avoid boxing / unboxing.
  
• Remove unnecessary boxing and unboxing code.
  
• In case you are using unmanaged code use the dispose final function for clean up.