Skill is related to Writing. Criticism is a type of Writing. 
Extreme is a synonym of Strong. Strong is a synonym of Substantial. Substantial is similar to Essential. Essential is a synonym of Critical. 
Skill <--RelatedTo--> Writing <--IsA-- Criticism 
Extreme <--Synonym--> Strong <--Synonym--> Substantial <--SimilarTo--> Essential <--Synonym--> Critical 