This is a very personal choice. Allowing for that,The proper ratio for upper to lower lip volume is 1 to 1.3. While your lips have beautiful shape and volume, if you like slightly more volume, you can respect this ratio while injecting of a small amount of the filler such as restylane or Juvéderm into the upper lip, especially under the "peaks" of the upper lip, and just slightly away from the center. Avoid too much injection in the outsides and corners of the upper lip, as they already have enough volume, and too much filler in this area can result in a "fish lips" appearance. seek an experienced injector, and always opt for smaller amounts of filler upon which you can add more volume in the future. Good luck!