Some more basic tips:
Your tips should not fold back on themselves when compressed, they should just squish.
Don't over-tape your tips, you'll make them too firm.
Technically, foam thickness is 5/8, but you're only going to find 3/4 out here. It's difficult to find sometimes, I recommend calling places in advance to see if they have it. Be sure to specify 3/4" WALL foam, because if you just say 3/4" foam, they'll assume you mean the pipe width, and probably sell you 3/8" wall foam, which is not legal.
Don't try to 'shave' foam down to make it thinner, you'll just mess up the foam.
Don't just poke holes in your tips with a pin. Stab it a few times with a knife. Your tips should compress quickly and spring back pretty instantly.
Remember to tape up the blade, not around.
Remember your 1" overhang, and remember to plug it with more (closed cell) foam.
These two things are the most common mistakes I see new weapon builders make.
If you follow the weapon building guide in the book (the step by step directions on p33) then you should be pretty good. You can take that base and add a head for an axe, shorten it for a short sword, or add open cell to it to make a club.
I recommend cloth tape rather then duct tape. Generally, 3/4" pvc is the standard, but you can do 1/2" for most weapons (especially short weapons). Make sure your finished product doesn't rattle. Have somebody else hit you with it pretty hard (not like baseball swing, but somewhat harder then nero legal), and if you're not willing to let somebody do that, then it's probably not legal.
~Matt