Sheet Module
Thisworkbook Module
Code Module
Class Modules
Below are some tips –
Turn off screen updating
Declare the variables and avoid the “Variant” data type.
Disable events
Using the WITH statement.
Avoiding the Select statement
Select Case instead of If Then
On Error Goto 0
On Error Resume Next
On Error Goto [Label]
Err Object
Err. Number
Err. Description of
Err. Source
Err. Raise
Error Function
Error Statement
Implicit Declaration: When variables are used without declaration is called Implicit declaration.
Explicit Declaration: Declaring variables before using is called Explicit Declaration.
Arithmetic Operators, Comparison Operators, Logical Operators etc.

new sample description here