Of the fillers which are in common use for volumizing structures on the face, the hyaluronic acid family, Juvederm Ultra & Ultraplus or Restylane/Perlane are excellent.  I usually ask the patients to not expect persistence of the effect for at least a year.  Their patience is rewarded by a low incidence of bumps and over correction to the "trout pout", which everyone dislikes.  After dosing, every 3-4 months for a year, there seems to be a retention of the volume.  The chief advantage of going slowly is that subtleties of arching the cupid's bow peek and the philtral colums, as well as everting the corners of the mouth can be done progressively. 

Structural fat grafting is also a perennial favorite.  What woman doesn't have excess fat, she's willing to shift elsewhere.  It really is replacing "like" with "like" because the fibrofatty tissues truly disappear with age.  The main difficulty is the need for a formal operation to harvest the fat and having a very tolerant patient who will allow regrafting under dental blocks. 

Hope this is helpful.  Good luck.