Nissan Micra has been launched now, but, bookings of the car has already been started. The petrol variants of this small car is available with only 1.2L, 1198cc engine displacement with 5 speed manual transmission gearbox that offers mileage around 18.6kmpl mileage. The mill of the compact four-wheeler produces 76PS of maximum power and 104 Nm of torque. It offers mileage of around 14 kmpl in city and 18.06 kmpl mileage on highways.
But Mileage of the car depends on your driving style, braking frequency, traffic and engine service.
For further details about the car please visit the given link as above.
We encounter similar question many times, the easiest way to increase the mileage is to keep your car healthy. Keep the tyre pressure proper, air filter clean, always follow speed limits and turn off your engine on traffic lights. Find more tricks here- Please find the details Chevrolet service centers here- http://forum.cardekho.com/topic/356-how-to-increase-mileage-of-your-car-tips/
There is not any special petrol recommended for NIssan Micra. You can use simple unleaded petrol in it. However, you can use Speed, Power or Extra premium petrol for better performance of the vehicle.