Demonic horns (photo by Daniel Lange) Demon Hunter Helmet, Dragon Warrior (Photo by Håvard Nyhus) Deer makeup and Demon Hunter Pauldron (Photo by Håvard Nyhus)
Demonic Horns A base of foam, tin foil covered in masking tape. Hot glue is used to make the ridges on the horns. Full tutorial here: Demonic Horns
Base is tin foil which is wrapped in layers of news paper. The paper is primed with woos glued to make it stiffer. Creates a scale effect. Full tutorial here: Dragon Horns
Large dragon Horn
For larger horns it can be an idea to use expanding foam. Build a grid of cardboard first, add foam and carve out your shape. Then the shape is covered with masking tape and then layers of news paper. More explanation under Demon Hunter Pauldron tutorial.
Horns for helmets
Same as with the horn above, the horns for the demon hunter helmet if made with an expanding foam base. This one id covered with hot glue to create texture. More details on how to make them in the Demon Hunter Helmet tutorial
These were made with a cardboard stencil wrapped in tin foil. Texture is made with glue gun. Full tutorial here: Deer makeup
I have also made a video about how to detach and attach horns for easy transportation.