Look up videos on PDR (paintless dent removal). The tools are expensive but you can make your own crude tools to get most dents out as long as you can get on the backside of the panel you need to work. That's the real trick is getting access to the backside to work the dent. Patience and you can push most of it out. The metal is super thin in our cars so they dent very easily. If you push most of the dent out then you won't need as much filler/block sanding to get flat smooth paint.