the helmet decals i had made at a local sticker kiosk in the mall, most of those guys can make a skicker of just about any image you can find on the internet, I had to look up the font online for the unsc and other letters, then just measured how big i needed them and had them make it.
The visor etching was done in 3 main steps, first was tape off the visor with blue painters tape and draw the etching on with a pencil, cut it out with an xacto, the second step what using a wire brush on my dremel and VERY CAREFULLY did the bulk of the etching, last I used the xacto to get any small corners or spots I missed. It is important to be careful with the dremel because the tape will only protect the visor for a second against the dremel, so I recomend taking your time and stay away from the tape as best you can, then go back and clean up with the xacto