I've noticed that most people on this forum send monumental amounts of useless information with their applications for no convincing reason. Aliens in the US, through wasting so much paper, are probably a significant factor in contributing to global warming as a result.
Here's what you need for AP renewal (and it worked for me):
1- Application
2- Fees (if applicable)
3- photos with A# and name written with pencil on the back
4- Proof of pending I-485 (i.e. I-485 receipt notice)
5- Photo ID (passport or driver's license)
6- Short cover letter only because the application asks for an explanation of why you need AP (in most cases, because you have a pending I-485)... even this is probably not required.
Optional stuff:
6- I-94 front and back IF you are subject to NSEERS (to show FIN#) and/or you are subject to the J visa home residency requirement and have your waiver from USCIS, in which case you should also include the waiver approval. This is because Advanced Parole cannot be issued to those without such a waiver according to the instructions.
Things you DON'T need to include:
1- Copy of all pages of passport
2- I-140 receipt (pending or approval notice)
3- Birth, marriage, baptism, or circumcision certificate
4- Letter from your employer of your school or your spouse
5- Your most recent grocery list to show that you are a healthy potential American
6- Copy of your previous AP - it's a previous AP and is irrelevant here
7- A picture of your family abroad to prove you have somebody to visit
8- You most recent electric or cable bill to show that you are responsible in making payments
9- A portrait of POTUS