I left out a few more sentences.
1)Finally, Jekyll and Hyde represent the double side of man's soul. They are the stereotypes of people who are good and evil. As Jekyll has lead a virtuous life, his face is handsome, his hands are white and well-shaped, his body larger and more harmoniously proportioned than Hyde's.
2) In contrast, Edward Hyde, who stands for pure hate and evil, is pale and dwarfish and his hands are dark and hairy. He gives an impression of deformity and is much smaller than his alter ego. When Hyde achieves domination over the Jekyll aspect, the latter decided to kill his evil side by committing suicide.
3) If you don't e-mail me a confirmation of my booking by tomorrow, I will have to cancel my reservation. Prior to booking my flight, I need a confirmation of my hotel accommodation.
In #2, because you begin with the present tense (When Hyde achieves...) and then switch to past tense (decided) which I would keep in the present as well (decides) This is called "sequence of tense."
Otherwise, well done.
Sra