From past few days I am very much confused regarding indexing wordpress tag or not. Few blog says its ok but another its not good practice since google panda ?? whats better ?
I have seen great content blogs ranking with their tags. There are many seo plugins for these tags to be optimized. I think you should try to optimize the title and description tag if your tags been reflected in the SERP's, this will surely help. Try to use the canonical option from the seo plugin which will indicate the correct page to the google. I think plugins are the best thing that you should try using.
It is better to use meta follow. noindex tag with the tags pages, this would allow Google to crawl all links on the page, but would restrict them to index the page and hence, this would also avoid duplicate content issue.