Oh goody, another person attempting EVA 01! I'll be attempting it as well.
Well first off, depending on the degree of realism you want, I recommend making a bodycast to sculpt the costume on.
will have some useful information.
I dont mean to sound mean, rude, or discourage you from anything, but I would not recommend doing your EVA-01 for your first costume. I went as Dart from Legend of Dragoon to a convention this year, and I had to cosplay for 3 years to get to the point where I could even attempt a costume like this. My previous 2 years I cosplayed Mobile Suits.
Once again, I wouldn't recommend it, but thats just my personal opinion.