Clipping masks are so perfect in photoshop. I use them all the time - for everything. The templates we make here pretty much all use clipping masks. It's such a simple but brilliant part of photoshop.
So in this tutorial I'm going to briefly explain how to make a clipping mask. Last week I went over using pre-made clipping masks in templates but if your design or a design you have purchased comes without it's an easy trick to learn and it saves so much time and energy.
Start by File > Open the template you want to use. Or, alternatively, open a blank canvas and draw a square or rectangle with the 'shape' tool.
I'm using one of my storyboard templates from here
The selected layer is going to be the 'base' layer, so the layer that defines the shape of the photo.
Next, drag and drop your photo into the document.
See how it is bigger and overlapping the layers below it? We want it inside the large grey box.
Make sure the photo layer - or the layer you want to show inside your shape - is just above the 'Base' layer. If it's not, drag and drop from the layer column. (If this is missing Window > Layers will open it up.)
Now select the top layer, the photo. Right hand click on the area and find 'Create clipping mask'
Your layers should then look something like this
The photo layer should be indented with a little angled arrow on the left hand side. The base layer is now defining what is visible of the photo.
Your photo will not automatically move to fit, so it'll just clip to the base layer where it is. This may mean you need to locate it and drag it into the space. In my photo, it's a little far over to the left.
Click and drag to move it around, make sure auto-select is off as this can make it awkward.
Once it's in place, you're done. On to the next one. Any layer (except text layers) can be base layers, any layers can be the clipped layers. It doesn't just apply to photos and shapes, so have a play around and see what you can do with clipping masks :)
There you have it, easier than it looks :) Let me know if you need any help, I'll be happy to assist.