Sorry if this is a stupid question (cause im on vacation and i cant do shit since i dont have my computer) but is that even possible for most people? Shadows in csgo dont really work unless you have a hella lot of good reflexes.
If you can see shadows, they're really helpful. Take cat on dust 2 for example, you can see people running down cat from CT spawn, and you can tell when they're about to jump down to you by looking at the shadows on the ground, I use that a lot in deathmatch.
just prefire if you see black on the ground, make sure you aim at head level. if they say "hacks" just ignore it because they obviously don't know the map well enough