Painting a repainted car?

I believe body work is a 'you have it or you dont' skill. If you're an artistic type, it might be a little easier for you to see curves and lines and shading. I see people hand sand a patch area, stand back and go "looks good!". yet, move the light around and it's like the Rocky mountains. Dont get me wrong, you can learn what to look for, but it just takes time and practice