Mate if you really want to take good care of the car you have to think all this. Normal cloth scratches the paint and the paint gets dull over the time. Its bound to happen in india with the amount of dust and all. No car can remain swirl marks free but still when i wash i don't use normal cloth but microfibre.
1. Better to give the car for professional wash in my personal opinion
2. If we have to do it, then we should buy that micro fiber cloth specially sold in interior shops and not the one on roads. Yes banian cloth is really good, even I use it some times
3. should use the Auto shampoos only and it applies for Wax too
4. rubbing can be done with a nice fibre cloth very lightly and I refrain myself doing the buffing with machine as it requires skill doing so