Cross-processing & Double Exposures

[nikkiweki]

I have a set of pictures that I took in sequence and I want blend them into one picture, I know there's a way to do this in photoshop, I just don't know how to do it well. Does anyone have any tips or know where I can find a step by step guide?

 

[Light Guru]

For the double exposures just place each image on a different layer and play with the opacity