local variables (used only in one subroutine)

integers       start with i     e.g. iCount
floating point            f          fRadius
currency                  c          cPrice   
strings                   s          sName   

global variables (used in more than one subroutine)

integers       start with gi     e.g. giCount
floating point            gf          gfAverage
currency                  gc          gcTotalInvoice   
strings                   gs          gsName    

constants (never change during execution of the program)

the name is all upper case except for the prefix
e.g.   gsCORPORATION  	is a global variable and it contains the 
                        name of the corporation
       fPI              is a local variable with value 3.1605    

object labels

command buttons    start with cmd     e.g. cmdExit
text boxes		      txt          txtQuantity
labels                        lbl	   lblStatus   

meaningful names

iTotalQuantity  is better than iTotal if there is also a total price variable
sLastName       is better than sName especially if you also need first names