Hide the sketches?

Keyboard Shortcuts that can save you time:

Here’s a list of keyboard shortcuts that some people might not know about.  Most of these can be discovered simply by hovering over any particular tool icon in Photoshop, but for reference here are the ones I use most.

• D — Restores the default Foreground and Background colors (black & white).
• X — Swaps the Foreground and Background colors
• H — Selects the Hand tool
• T — Selects the Type tool.  Shift + T rotates through the different types of Type tool (Horizontal, Vertical, etc.)
• M — Selects the Rectangular Marquee tool.  Shift + M alternates between the Rectangular and Elliptical Marquee tools.
• V — Selects the Move tool.
• L — Selects the Lasso tool.  Shift + L rotates between the different Lasso tools (Regular, Polygonal, Magnetic).

Basically, any tool that has multiple types (e.g. the Lasso, the Eraser, the Pencil) has a shortcut key assigned to it, and using Shift + that key will alternate between the types.

Actions:

“Actions” are a pre-recorded series of commands that can be played back on a single file or batch of files, allowing you to automate repetitive tasks.  Actions can be used to perform relatively simple tasks like resizing an image, to amazingly complex tasks like turning a picture into a polaroid photo tacked to a bulletin board.

Way back in 2003, Tim Plumer at PeachPit wrote a pretty comprehensive guide to Actions.  He covers everything over the course of 6 pages, so rather than reiterate what he’s already explained, here’s the article:
Take Advantage of Photoshop Actions.