Make clear what you are and are not willing to do. Work
from a DO list - quick business lunches, formal dinners at
holiday time. Also, work from a DON'T list - curry favor
with government officials, make or take payments of cash,
promise favoritism, participate in off-the-books transactions, etc.
Under the table payments, etc., are not to be done.
Every decision you make and enforce is observed and analyzed.
Do what is right.
Take the time to make your expectations very clear. You
will defuse may potential problems.
Some things may take longer than if you pay a bribe. However,
if you are firm and maintain a constant focus on efficient use
of resources, you will achieve good results.