Dear i would like to answer.
First of all no question is stupid. Dont be ashamed of asking.

1. You should not pay any random person to check your essay. There are many well renowned professionals e.g Mam Ayesha younas.
2. We dont need to write headlines in between essay.
3. Any book covering all topics is fine.
Regarding your other questions.
Join any test series conducted by academies , it will clear your mind.
I hope iy hrlp