主语：He
谓语：felt
宾语：两个并列1.从句that the eyes of Dorian Gray were fixed on him
2.单词the consciousness
the consciousness 的同位语从句：that amongst his audience there was one whose temperament he wished to fascinate seemed to give his wit keenness and to lend colour to his imagination.
同位语从句是there be sth + 地点状语的结构：one=sth,amongst his audience=地点状语；
修饰one的定语从句：whose temperament he wished to fascinate seemed to give his wit keenness and to lend colour to his imagination.
he wished to fascinate前面省略了that/which,是temperament的定语从句,先放一边,简化一下：
从句whose temperament seemed to give his wit keenness and to lend colour to his imagination中,
谓语动词seemed接两个并列的不定式：1.to give his wit keenness 和 2.to lend colour to his imagination；
而that/which he wished to fascinate中,that/which指代的先行词temperament是fascinate的宾语.