no.1 = Food .. what food you feeding? if the supermarket food, yes that is what you get. try to change to at least premium cat food like royal canin, science plan, proformance, iams, etc.

n0.2 = on heat and stress ... if you cat is not neuter/spay, stress and on heat can drop their fur. stress and on heat cat - when they are horny, they won't groom theirself.. all in their head is sex sex and sex

no.3 = grooming ... frequently groom your cat, which include, brushing/comb their fur everyday to make them nice. bath with good shampoo like from coconut oil (back 2 basic product), and a conditioner will make them look nice. if you have money, bring to grooming shop