No tool is more important than EQ when making a mix. EQs allow you to carve volume away from select frequencies of a sound in order to make room for the other sounds in your song. Having a clean mix means that every element in your track has its own place and can be distinguished from the other elements in the song. Of course there are other mixing tools producers use to achieve clean mixes but every sound is comprised of frequencies and if you can get those straight your mixes will really shine. Try applying these EQ tools to take your mix to the next level.