@iPersuade has some suggestions. I would recommend them, too:
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Tagging can be a pain, so doing it automatically has its charme: use Hazel for that if possible.
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Applying tags manually can be done with LaunchBar but also… with the Finder (just select a file, hit command - I and enter your tags in the tags field. I also use Leap, which is an awesome way to browse and manage files.
I am a little confused regarding your post in your second topic about tags. I think there are some answers to your question. 
Actually, the exact same apps have been mentioned:
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@csf111’s post: Finder to add tags manually
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@Mpacker’s post: Hazel to add tags automatically