There are more ways to show your car you love it that I can think of and you may know what i'm going to type, but here it is anyway:
1. Get emissions tested every year (i'd say once or twice)
2. Before and after every long ride, see if your tires need air.
3. DON'T WAIT TILL THE LAST MINUTE TO REFILL YOUR GAS TANK!!!
4. Check your oil once or twice a year
Good luck w/ u'r cars.