There are not too many places I can send you that will help with the creation of the Rebel Fleet Trooper, but there are a few...
SWtroopers.com has a great tutorial on identifying the parts of the RFT costume. They also have some screenshots from the movies that I do not have.
Bubba's Barnyard of Costumes is about the best place to go for generic costume making tips.
The Rebel Legion Discussion Forums and the Dewback Discussion Boards are nice places to talk to other fans about the Rebel Fleet Trooper Costume. You need to "register" to the forums to post questions.
The Parts of Star Wars website has information about the DH-17 blaster that the Rebel Fleet Troopers carried. Very informative website. Bookmark/Favorite this link NOW!
Does anyone klnow of any books or magazines that have images of the Rebel Fleet Trooper costume in it? I know I do not. Not even the OUT OF PRINT Star Wars Story Book has images of the Rebel Fleet Trooper inside of it.