After the wound has healed completely your best option is to protect the surgery site from the sun. This would include the use of a broad-spectrum sunscreen (i.e. screens out UVA and UVB) with an SPF of 30 or greater and other sun-protective measures (e.g. wearing a hat, seeking shade, etc). As long as the incision site is pink (and even beyond), the scar will be more sensitive to sun exposure. So, sunscreen and sun protection are very important.
Another good treatment is a silicone-based product. These bandages or gels help to soften the scar, improving slightly the final cosmetic result. One product that many of our patients use is BioCorneum, produced by Advanced BioTechnologies. This product contains both a silicone gel and sunscreen and is applied twice daily. BioCorneum is available only in some physicians' offices, but there are other products available that could help.
In my opinion, I think that sunscreen, sun-protective measures and silicone based products work better than the other types of available products. Talk to your doctor and good luck.