you can do that by opting two methods one can be that you can search for the relevant keywords on the Google search and the best option should be to try the Google keyword tool which will let you know about the global as well as the monthly search traffic on the particular keyword you are trying to target.
Just like tompatrick said you use the google keyword tool to find keywords for your site after finding your keywords you can start optimizing your site by building links for it, you can post links through blog comments, forum posting and so on.
find similar websites and check what keywords they are using. You can choose targeted keywords by google adword tool.
update your information about gadget from pupular web gadget... get many reference about that gadget and publish your uniq article... for SEO.. you can use plugin AIO and STT2 for support your keyword... BOLD and give link to link your article Underline keyword to your link article For improvement you can add pictures and give alt name with your kyword