Learn about the Pain Frequency which is actually the upper-mid range frequency, and the main idea is to cut out the most problematic frequencies in mixing, especially with the newer mixers who have little experience with the 2K range and that is usually called the pain frequency. This is a frequency which sounds exciting, sounds edgy but is not soft to listen to always. These over-hyped sounding tracks actually cause pain to the listeners as it is not pleasant to the ears. It becomes even harder to hear the vocals properly. So the target should be to cut 2K out of a lot of mid-ranging instruments to improve vocals.