This is a description of my use of keywords and smart collections in Lightroom 3 to get an efficient workflow.
I have the following keywords set up for my main workflow and processing my images as a preset in LR3:
I use the keywords in my workflow in this manner to send an image to a smart collection:
When I go through my images in a folder I will use the "#CAN: candidate" keyword to tag images that look promising.
I then go into the candidate collection and make decisions on which images I will not use after all (remove the candidate keyword), or tag with a "develop" keyword if I want to use the image (and then remove the candidate keyword) to send it to the next smart collection that is where I have the images that need adjustments in LR develop module.
After develop I will either send the image to my print smart collection indicating that the image is finished and ready for use, or I will send it to my PhotoShop smart collection if the image need a round trip to PS (usually) before going to the print collection.
By setting up a preset of work flow keywords and matching smart collections this is a fast and easy way to have images i various stages and it's easy to find the images I'm working on or that is ready for printing/use.
Just remember that when you move an image from one collection to the next, add the new keyword before you remove the old. If you don't the image will disappear from the smart collection before you can send it to the next and you will have to find it again in the main catalog.
I star mark the final images after how much I like them.
I have a separate keyword set and matching smart collections to indicate different usages of the images.
I will of course also keyword images in the normal way with location, names etc. to make any search easy, and use the following keywords to track the process of keywording my images.
I then have smart collections that contains:
The original idea to use these keywords is from the Lightroom Journal.
Ronny A. Nilsen
Norway, October 2008
Generally you don't want to export these keywords with an image, so just right click the keywords and select "Edit Keyword Tag" and uncheck the "Include on Export". That way you can export the other keywords from LR, but exclude your workflow keywords. Until you export all keywords will only be in the LR database anyway.
The reason I start the workflow keywords with strange letters, is to get LR to pop up all the alternatives when I type the first letter. So when I type '#' I get a list of the workflow words I use. This then gives easy access to them even if I use another keyword preset at the time.