Check out the degree to which your car conforms to or deviates from the typical Indian car -
Q1. Does it have something hanging from the rear-view mirror?
If you running out of ideas, popular candidates are, teddies, bunnies, CDs, toys, beads/garlands, air freshner - particularly the leaf pattern, Chinese Feng Shui stuff, flowers - both fresh and artificial, piece of cloth (especially the holy ones), crystal...
Q2. Does it have a box of tissues?
Ideally an ornamental box sitting in the back.
Q3. Does it have God or some other 'holy stuff' sitting in the middle of the front deck/dashboard?
Plently of choices here too, could be an idol, a cross, you get the picture I am sure. If you want to go beyond the ordinary, you could offer flowers, agarbattis and what not.
Q4. Does it have an air freshner bottle on the front left?
Minor deviations are possible on the position and type.