I can't study if people are talking, someone is tapping on the floor with their fingers, the clock is too loud, etc. But at the same time I can't study either if the environment is so silent that my ears just start ringing. I study with music on the side--usually Ed Sheeran or Sam Smith. I can't study with just paper, I always need my laptop. For some reason my brain retains more info if I see it from a screen and I type the words myself. I re-type my notes as many times as needed until it sticks to my brain.