How do I repair car dents?

My car has been the unfortunate victim of two hit-run drivers, just weeks apart. One dent, quite substantial, is just below the fuel filler on the left side and is quite substantial. The other dent is on my left front fender and is quite significant itself, as far as damage. How do I fix these dents made by hit-run drivers that were never caught? I have a 1997 Kia Sephia with an automatic transmission. Thank you!