Here's how I prepared two N-400 applications (one for myself and second for my spouse).
The order of package:
1. On top, Two passport size color photos in a transparent ID holder (got it from walmart I think craft section - it looks like this:
http://www.walmart.com/ip/Advantus-Proximity-ID-Badge-Holders/14918622). I didn't buy the box shown in the link but got a smaller pack with 10 or 20 covers/holders in it.
2. Check for $680 (each signeed their own check). I wrote A # on the top left next to the address area. On the for/memo line at the lower left, wrote "Fee for N-400 application and biometrics"
3. 10 pages of the form n400 plus one additional page because information in one of the sections was too long to fit in the boxes provided. I wrote "Please see attachment - Exhibit A" in the N400 form (for example in the employment section because the names of the employers were spilling over.
4. Copies of front and back of green card
I first set of papers for mmyself into on yellow 9x12 clasp [image: http://s7d5.scene7.com/is/image/Staples/s0069356_sc7?$splssku$] and wrote
Form N-400
Name of the applicant
A#
I put second set for my wife into on a second yellow 9x12 clasp envelope [image: http://s7d5.scene7.com/is/image/Staples/s0069356_sc7?$splssku$] and wrote
Form N-400
Name of the applicant
A#
Then I put both of these envelopes into one priority envelope (the hard kind, don't know what you call them) and sent it by priority two day. Also attached signature confirmation. Total cost $8.30
According to the USPS clerk, it wil out today at 2:30 PM and will travel through the weekend to get there on Monday most likey in the morning but not guranteed.
Hope it helps others in similar situation. I know I had questions about every little detail. Will keep you guys posted on what happens next.