What is the best way to reduce smile lines?

Fillers: Smile lines are the consequence of smiling - in itself a good thing. As we age our muscle tone and skin flexibility lessen , thus the smile lines. Fillers are probably the best for lessening them. But, they need to be continually replaced - so you may be in for a long and costly routine. No long term studies about the condition of the face after 15-20 years of this. Careful what you wish for.

Depends: If you're talking about lines around your eyes when you smile, the best treatments are Botox or facial resurfacing with a laser. For the parenthesis lines around the mouth you will get a better result with volume replacement (fillers like hyaluronic acid or collagen stimulators like sculptra or fractionated laser).