How to increase my ranking in Google?

Hello everyone,
I have a supplements related web site (newflexprotex dot com) and I am working with 2 keywords Flex Protex, Flex Protex D since 3 months and regularly the keywords ranking is decreasing. I need your help guys what are the best way to increasing these two keywords. You can suggest in Off page optimization or On page optimization.

See original post by bprusty