Questions about the IGCSE first language English.

I have quite a few questions regarding the Cambridge IGCSE exam in first language English. It would be appreciated if anyone can give me some advice.
Is it possible to get a hold of old marked papers for IGCSE first language as I would like to see the difference between the answers of a student getting full marks for the question and the difference between someone that only got half marks?
Can anyone give me some advice regarding putting together ideas for a question for example that is asking to write about a particular topic like having a clear idea as to what I will be writing for each paragraph, if you can't do this on the paper itself, what is the best way of going about it?
What is the best way for me to learn a more varied form of vocabulary for the exam?
How can I increase my confidence in overall creative writing?
Can anyone suggest a good guide where I can mark my own writing?
What can be done on the paper if you have covered an area but once looking over the answer you forgot to add in information that is needed. Can the information be written beneath the the answer with an arrow pointing to where the text should have been, if not what is the alternative?