Trick Photoshop

Step 1 : I have opened this free stock image. Open any image you want.

Step 2 : Open the Custom Shape Tool. You can see where it is to be found.

Step 3 : Click where the red arrow points to in the top panel. From the drop down I have chosen the envelope  shape. Click to select.

Step 4 : Draw out the Envelope shape like I have done.

Step 5 : CTRL+Click the Vector Mask thumbnail the arrow points to.

Step 6 : As soon as you click the Vector Mask a selection of marching ants forms. Press CTRL+SHIFT+I. The selection reverses.

Step 7 : Drag the Shape 1 layer to the trash can at the bottom of the Layers palette.

Step 8 : Click the New Layer icon in the Layers palette and a new Layer 1 forms.

This is how image looks. The Vector Mask has been removed, but the selection remains in place.

Step 12 : This is how the image looks with the Gradient applied. Press CTRL+D to deselect.

Step 13 : Click where the arrow points in the Layers palette to bring up the Blend Modes. I have clicked on Hard Light which suits my image. You can see which Blend Mode suits your image.

This is how my image looks after applying the Blend Mode.

Step 14: Click the Add Layer Style button  and click on Outer Glow.

This is how the image looks.

Step 16 : Click on the Crop Tool.

Step 17 : I have cropped the image.

Step 18 : Click the Tick mark in the top panel to apply the crop.

And, here's my image.

Add some suitable Text. And, there's the finished image.

Other Photoshop tutorials are here.