Credit and Debit

The usual concept of Dr. and Cr. for any increase are:
A . Dr. expenses Cr. income
The net difference is the net profit as reflected in the Profit and Loss Account ( Income Statement )
B. Dr. Assets and Cr. Liabilities and Cr. Equity ( Share Capital Reserves ( Profit b/f this year's net profit[Net balance of net profit in A] )
This is how the Balance Sheet is balanced
For example, if you pay electricty $100 by cheque, then Dr. Electricty ( Expenses ), an increase in an expense and Cr. Bank ( Assets ), a decrease of an assets.
So, the formula is
Assets = Liabilities + Equity ===>
Assets = Liabilities + Share Capital + Reserves ===>
Assets = Liabilities + Share Capital + Retained Profit b/f + This year's Net Profit

以中國概念嚟講，有付出才有收穫。資產是借方(Dr)而負債及股本是貸方(Cr)。因為你做咗一個銷售行動，你的回報是資產增加，所以增加資產是借方，其相應收入就是貸方。你享受服務及消費，換來是債務或減少資產，所以借方是費用，貸方是應付賬或者減少手持現金等。
希望幫到你！