What are the the best Accounting Methods (Principles) that gives tax advantage to business organizations?

It depends upon Tax laws of each country, however below is the summary of general tax avoidance practices which has been followed in most of the countries:

1. Transfer mispricing - transactions between associates located in different tax regions

2. Double taxation agreements gives relief from certain taxes

3. Tax sheltors such as Foreign Leveraged Investment Program (FLIP) and Offshore Portfolio          Investment Strategy (OPIS)