The key to making a template is to make everything impermanent. It may be a challenge, but there's always a way to make a change temporary in Photoshop. You just have to find loopholes!
A template starts with a blank white or black canvas. I started mine with a 5x7, 300 px resolution white canvas because 5x7 is a nice, standard photo size that can easily be changed to either 8x10 or 4x6.
Let's begin with something simple. Using your rectangle tool, make a shape that covers roughly three-fourths of the canvas in the opposite color (for instance, I have a white canvas, so I'm making a black rectangle.)
Now, make another shape in gray. This can be any shape you want from the Photoshop presets. It should be between half and two-thirds the height of the canvas and however wide as you see fit. You can always change the size as we go. Place it where you think a photo would look nice.
Use Ctrl+J or Command+J to duplicate the layer twice. Line the three objects up so that at least two overlap your black rectangle. Look! We already have some sort of design. This is technically already a generic starter template.
ADDING PHOTOS
Place your photo over whichever shape you want it to occupy. Resize as needed.
With your cursor on the line between the photo and the shape layer, hold down your Alt key and click the line. This is called creating a Clipping Mask. The photo will only show up where the shape is. you can move the photo around to get the correct placement.
From now on, any changes you make with the shape layers will be applied to the photos. For instance, if you change the gray layers to "Hard Light", the photos will appear to be set to Hard Light although they are still normal photos. You can change the Blending Options any time you want.
Part two will come soon enough. For now, experiment with this method. Make your own different starter templates, and show me what you do! :)
