Want to talk to someone. Use "ama" (means "yes") frequently.
Yes, it is the thumb rule and see the development. Your work will be done relatively faster. But do not give an impression that you know the language. Just give an impression that you people are most unbelievable race on the planet (never mind they are a collection of rowdies, they know it.)
10. Rule - 10: --------------
While taking a house, make everything clear.
Yes, make everything clear to the owner, the water, the electricity amount to be paid, your timings, your food...everythingfrom A to Z.
When you see a house, the owner will be the most descent creature on earth. Later on first casualty will be your early morning chores. Madras is city without water and in summer seasons very few take a descent bath. If you are non vegetarian make it clear to them. House shifting is pain.
11. Rule - 11: --------------
Always use markets or places where people can speak in English.
This way you will not get cheated and will be able to understand what they speak. Never ever try to learn Tamil. Trust me you will loose more than gain if you try to learn this medieval language. If you try, first casualty will be your English, second will be the change in personality. I can safely vouch for it.