Variable Naming Convention in ABAP

Here are some rules that I used for my convenience in coding ABAP. You can also have your own style in naming the variables in ABAP. These naming convention might help you remember and differentiate variables that you used, but keep in mind that you might need to follow a different naming convention in every project.

Variable Type	Usage
Global Varibles	gv_<variablename>
	d_<variablename>
Local Variable	lv_<variablename>
	ld_<variablename>
Global Internal Table	it_<internaltablename>
	gt_<internaltablename>
Local Internal Table	lt_<internaltablename>
Global Work Area	gw_<workareaname>
Local Work Area	lw_<workareaname>
	wa_<workareaname>
Constant	c_<constantname>
Parameter	p_<parametername>
Select_option	s_<selectoptionname>
Ranges	r_<rangename>
Type Structure	ty_<structurename>
Subroutines	F_<subroutinename>
	FORM_<subroutinename>

Source: 

https://archive.sap.com/discussions/thread/531835