1. A different way to mask
Open Photoshop. Select File > New. Create a new file of any size with a transparent background and click OK. With the Rectangular Marquee tool, create a series of boxes. Hint: Press and hold the Shift key to create a group of boxes. Press D on the keyboard to set the foreground and background colors to default black and white. Next, select Edit > Fill. Select Foreground Color from the Use drop-down menu in the Fill dialog box and hit OK.

2. With the Move tool selected, click the Create a New Layer tab in the Layers Palette. Select File > Place to place an image on this new layer above the boxes and click OK.

3. In the Layers palette, place the mouse between the two layers and Option-click. This will group the top layer into the bottom layer.

4. The benefit of using this method of masking is that both layers are kept intact without losing any pixel data. You can release the group by Option-clicking again between the layers.

5. Blend shortcuts
Use these shortcuts to blend layers with any of the blending options avaliable. With the Selection tool selected, press Shift + Option and the following keyboard shortcut letter:

Normal - N
Dissolve - I
Darken - K
Multiply - M
Color Burn - B
Linear Burn - A
Lighten - G
Screen - S
Color Dodge - D
Linear Dodge - W
Overlay - O
Soft Light - F
Hard Light - H
Vivid Light - V
Linear Light - J
Pin Light - Z
Difference - E
Exclusion - X
Hue - U
Saturation - T
Color - C
Luminosity - Y

6. Move the Marquee
This is a simple but useful tip for selecting an object with either the Circular or Square Marquee tool. If you happen to start out in the wrong place and need to continue expanding the marquee, you usually have to stop and start over. But by pressing the space bar while in the process of creating a new selection with the Marquee tool, you can move the selection and continue to expand it after it has moved.

7. Navigate layers
Press Shift + Option + ] to jump to the bottom layer in the layers palette.

Press Option + ] to select one layer above. Press Option + [ to select one layer below.

To quickly load a selection on a particular layer, press V to load the Selection tool. Press Command while clicking the image thumbnail on the layer you want to select. This will select any pixels in that particular layer.

Option-click the visibility icon of a particular layer to view only that layer. Option-click again to turn the visibility of all the previously visible layers back on.

8. More shortcuts
Create a new layer by pressing Shift + Option + Command + N.

Change a layer’s opacity by 10 percent by selecting the layer and pressing 1 through 9, or press 0 for 100 percent.

Bring a layer to the front or back by pressing Shift + Command + ] or [.

Fill a selection or layer with the foreground color by pressing Option + Delete.

Fill a selection or layer with the background color by pressing Command + Delete.

Change brush sizes by pressing [ to increase and ] to decrease.

Access the Levels palette by pressing Command + L.

Access the Curves palette by pressing Command + M.

Access the Hue/Saturation palette by pressing Command + U.

To apply the last filter, press Command + F.

Step backward in the History palette (multiple times, instead of just one level) by pressing Option + Command + Z.

Step forward in the History palette by pressing Shift + Command + Z.

Paste whatever is on the clipboard into a selection by pressing Shift + Command + V.

Hide or reveal a selection by pressing Command + H.

Hide or reveal all palettes by pressing the Tab key.

Reveal keyboard shortcuts or create your own by pressing Shift + Option + Command + K.