Lately I have been doing an AI or PS tutorial a week to sharpen my adobe chops. The tutorials I find are a great way to learn about tools and techniques that you might be rusty on, or not know about. This is a Photoshop tutorial that really works with color and blending modes well. I used my own free and purchased stock images. Feel free to use any images from the tut link ( http://wegraphics.net/blog/tutorials/make-a-retro-space-themed-poster-in-photoshop/ ) or use your own to make it yours.

My version.