For new cars, I do the following to keep it sariwa over the years.
- Keep it stock
- Park at covered areas
- Regular wash, vacuum and wax
- Don't smoke and avoid eating in the car
- Don't use strong air freshener (I made this mistake, more than 10 yrs after and my car still smells like California scents coronado cherry

)
- Don't overload (lakas makalaspag niyan

)
- Regular maintenance
- Immediately fix scratches, dents, bangga etc (if you leave it that way and you get another scratch or dent etc tuloy tuloy na, they you'd think marami na naman tama)