I tried to increase a particular keyword (for example: keyword A) in my blog by building more backlinks and contents (which aren't really related to keyword A) linking to it. Before I ran the whole process, the SERP for keyword A was 40's and after all the efforts above were done, later I found out that the SERP for keyword A has dropped significantly that it has fallen more than 100! What do you think that I have done wrong here? Could it be because all the contents containing 'not-so-related' keywords and contents I've posted linkining to it (Google SEmantic has penalized it)? Another info, all the titles in those additional contents contain the keyword A.
Maybe you experience the effort of google dance. Probably the search engine needs time to re-evaluate the links. Maybe your competitiors do more link-building. Maybe some of your old links do not work anymore (broken links). Hope you get to the first page soon.