Alien Resource Pack

Hello I am making a Alien map at the moment which you can see here http://www.planetminecraft.com/project/alien-returns/
and I want to make a resource pack for sounds and textures. I have made a texture for the walls just as a test to see how good it looks.

I know it doesn't look the best but I would like opinions on how to make it better because just the vanilla textures are good but I want to look more like this

I hope you guys can help me and I will post more pictures as i make more textures.