Tipping is optional. A 10% service charge is usually added to food and accommodation bills by the restaurant or hotel.
However, you can tip the worker directly as a way of showing your appreciation for services rendered. The rule of thumb is generally 10% of the total bill due.
For valets and hotel porters, tip anywhere between Rs.50 to Rs.100. Drivers expect a tip, as do people who ‘guide’ you through a site. If there is no money involved, use your discretion: Rs. 10 for the person who minds your shoes at temples.