Don't know that I can add much but...
I also smoke in the car. Started to on a road trip. 1 window open (usually drivers side). Vent on at combo floor/forward. I close the driver's side vent.
After, I use febreeze. There is a smoke eater I have also used, but I try to stick to similar types of scents like febreeze or fresh linen or fresh cotton (they all have their own cute names.) I absolutely stay away from fruits or evergreen- not because I don't care for them, but because they don't help detract from the cigar smell.
I get my car detailed once every few weeks. This part is CRITICAL. Ashes WILL wind up in your car, and they WILL build on one another. I don't know if you've ever put your face into day-old cigar ashes, but they stink to high heaven. If you have dropped any ash notably in your car, get them out. Otherwise, vacuuming and wiping all of the ashes up is critical in the long-term. Also, it may just be me, but I think the baby powder spray at the car wash totally eliminates the cigar smell.
Bear