The following are just some very basic tips on how to work more efficiently in Photoshop.
For print: do 99% of your colour corrections in RGB with the CMYK Proof turned on rather than directly in CMYK. The colour change should happen at the last possible moment and be sure to retain a copy of the 'source' file in RGB whereever possible.
USE THE PIPETTE. Look at what colour castes you might be getting by looking at the Info Palette. WYSIWYG is relative to the quality of your monitor, colour profiles, destinations, etc... the Info Palette is then your friend.
ALWAYS use Adjustment Layers to make ... adjustments ... rather than modify the original data. This will make your life much easier in the long run.
Tones are typically 'smoothed' automatically with a mode change but if the image is to stay in the same mode, I typically change the image size by 1px to achieve the same effect.
Sharpen in small increments multiple times rather than try and get it 'perfect' right from the start. Depending on file size I would normally suggest USM with a setting of 50,1,1 repeated until you get the desired result.
Consider using Smart Filters to make review easier later on.
As above... rather than resize a file to 25% of it's original size and sharpen it 'perfectly' in one hit, resize 50%, sharpen, resize 50% & sharpen. Experimentation in the key.
I always retouch or heal images to a separate 'retouching' layer. This enables a reality 'check' as you can review before and after very quickly. It also allows you to correct your corrections well down the line.
Important though is to retouch with all adjustment layers turned off.
Bear in mind that USM applies to the selected layer rather than an entire image so maybe consider sharpening close to the final colour conversion.
Place images (File/Place) to create smart layers rather than copy & paste various elements in. This is especially powerful when you utilise vector art as you can then enlarge the files without issue later on. It also has the advantage of naming the layer with the source file name automatically.
You can use but can't link masks to smart layers (not sure why) but you can apply the same mask to a set and insert the layer into that set. This allows you to move it around freely.
You can create multiple masks on the same image data by using sets. A classic example of this is a deepetched apple that should fade at the bottom. The apple is masked out and then put into a set with the gradient mask.
NAME YOUR LAYERS (especially important when using stock images), NAME YOUR SETS, NAME YOUR ADJUSTMENTS.
© Christopher Young, 2008