Don't drive it
My main rules are no eating in the car. No one is allowed to drink or even bring beverages in the car. If I have a beverage, it's in the cupholder but I have a microfiber layed out in the cupholders and place the cup on top of that so even if you get a drip or two, there's nothing getting dirty. Kick your shoes together before swinging them in to the car. Windows up as much as possible.
Quick vacuum of the car every 4-5 days. Wipe down the interior with a dry microfiber or with a little detail spray every Friday or Saturday.