It is normal to have visible pores, but they can enlarge with aging, acne or sun damage.  It is important to use oil-free products to not cause clogging of the pores and you should exfoliate once or twice a week.  Tretinoin cream helps keep the pores unclogged. Several treatments can minimize the appearance of pores, but will not eliminate them.  Light chemical peels and microdermabrasion will help somewhat, but laser treatments such as the fractional co2 laser are more effective.  A series of these treatments is usually necessary.  Sun protection is important.