first of all you need to know the provision of GST , When applicable SGST , IGST and CGST, it is more important than accounting entry. usually same entry previously done.
first oa all you know about your sales product HSN Code and rate of GST. than secondly know about place of supply. if your supply with in state your tax decide in wo part SGST and CGST. for example your product GST rate 18 % ,and your registration state is Gujarat and you supply the material in Gujarat then your accounting entry as follow ,suppose basic value is 100 , Party Ac debit 118 sales ac credit 100 SGST AC credit 9 CGST AC Credit 9