As office-dwelling nerds, we have a lot of stuff on our desks, including a few DIY projects from some of our favorite games. This PixelBlock Napalm Man is part of Brelston's menagerie of Mega Man / MH / Marvel silliness.
Once you have the actual building materials, you need to find a good image of the sprite you want to build (a simple Google search can lead you to many sites that specialize in those assets) and then slap that sucker into PhotoShop or another similar program so's you can toss a grid over the image.
From there... you build! I start with the feet and then build up from there. Once you're done, consider adding a couple of extra blocks around the feet for stability; these finished pieces can technically stand up on their own, but they're only one block thick, so the extra blocks around the feet help prevent tipping (which can, uh, really suck when the pieces fly everywhere).