Open Fireball.psd and drag into your image below the 'Smoke' folder. Select Blending Mode > Screen. Scale, rotate and duplicate each layer until you’re happy. Erase areas by generating selections from your alpha channels and also a selection from the mask on the 'City' layer. Next, drag all the layers into a new group folder and name it 'Fire'.
Add some alien death rays by drawing a closed path and generating a selection. Ensure white is selected as your foreground colour and Foreground to Transparent is set on the Gradient tool. Add a new layer at the top and add a gradient, duplicate, rotate and scale for the remaining saucers. Merge them, and select Blending Mode > Soft Light. Duplicate the layer and add a slight Gaussian Blur, select Blending Mode > Normal and the Opacity to 60 per cent. Add some glow by using a white, soft brush on a new layer, setting the Opacity to 70 per cent. Drag all these layers into a new group folder called 'Rays'.
Open Models.jpg. An easy way to isolate the figures is to create a density mask: inspect the channels to see which one holds the most contrast – in this instance it’s the blue. Duplicate it and hit Cmd/Ctrl + L to access the Levels; and drag the midtone slider to the right and the white point to the left. What you’re aiming for is a clean silhouette of the figure.