I would say its a combination of two things. Writing more often is fantastic but it will only get yu so far you need to expand your vocabulary outside of what you know,this is done by reading or conversing with people that have a superior vocabulary to yours. At some stage you will hit a ceiling, we are genetically predisposed to be really good at some things like music, math, language logic ect ect. This is why we arent all mathematicians or book writers