My first suggestion is to take a look at build thread here and have a look through, then look around the sight all the info you need is there. I am also comprising a comprehensive list of required materials and helpful tips and tricks of the trade for people to look at here. I will be posting it in my journals section
I would have rubbed it down with some Minwax stain, then quickly rubbed it off - this fills in all the scratches and makes the whole thing look weathered. Awesome job, but the colors are too bright - any Space Marine would have seen many battles and rarely have such clean armor.