First of all:
COMPLEX SENTENCES!!!
Where the fuck are they? Look at these:
Kate has a step-dad. Kates dad is 36. He likes to swim.
And:
Kates step-dad is 36 and enjoys swimming
The 2nd one sounds better.
Things like:
The rusty knife slowly penatrated her lightly tanned skin
Sounds a lot better than
The knife went in her skin.
Also the story was very predictable and I dont suggest startin a paraghraph with dialouge, this makes it harder to describe the atmospheare like:
"I think we are going to die" Janet whispered to her friend
and
In the dark and dingy room, Janet whispered to her friend
"I think we are going to die"
Also every speech has its own seperate line.