會計做一盤帳, retail公司同trading公司的做法有咩唔同?

Strictly speaking, not much difference. The only account that maybe important is the Cash Sales Account. Moreover, you have to open sales account and cash account for each retail outlets. The daily books must be balanced and the cash must be checked and bank in intact daily, credit card sales must also be checked and debited to Credit Card Sales Receivable.
There is no difference in Profits Tax submission.