I honestly have no clue what 'muddy' sounds like and no clue how much high end is too much. I'm told some of my mini bass projects are muddy. I sidechain , high pass sounds that do not need the low end , attenuate a bit around the low mid range , and reduce the frequencies of sounds that are overlapping my lead sounds. These are all things you are told you should do but the only thing I can really do and hear a difference with is sidechaining a kick and bass because usually you wont feel the kick because of the basses low end. Also , I understand you should cut overlapping frequencies that cover the lead sounds loudest or noticeable frequencies but if you have 3 overlapping a sound rather than 1 overlapping another do you attenuate frequencies more and more from most important to least important sound?