I have a package of wipes and bottle of sanitizer in each car. I use them on my hands and anything I touch, once I get into the car, including steering wheel, gear lever, keys, etc. I don't really use my phone when out and about, I've switched to a paper grocery list for the time being, which gets tossed in the trash when I'm done.
And of course wash hands thoroughly when returning home. We also wipe down with bleach wipes, every door handle, light switch, and sink handle we tend to touch, when coming into the house from outside.