It started with a bloodied sky

Hiho, dudes and dudettes! So, I don't consider myself a "graphics artist" But I've decided to make a deviant account, because I thought it might be a good way I can learn any new tips. I welcome any and all suggestions and help that you guys might have!

This first image, I made for my Post apocalyptic BTVS, TW AND SPN role-play site.

Resources

Wooden leafy window - rachellcoe.deviantart.com/art/…
Shattered glass brush - archaii.deviantart.com/art/Sha…
Apocalypse girl - seleniafrost.deviantart.com/ar…
Grass 01 - www.freeimages.com/photo/menhi…
Grass 02 - www.flickr.com/photos/mikecatt…;
Clouds - www.morguefile.com/archive/dis…