#1 Have a full size spare tire to start with.
#2 have a working jack and lug wrench and a pipe to extend the lug wrench handle for when you get new tires and the garage/tire store puts the lug nuts on way too tight (I don't care if they rotate your tires for free, do it your self, it will save you someday)
#3) tire plug kit and 12v compressor and pressure gauge should be standard equipment in a vehicle kit