http://databases.about.com/od/specificproducts/a/3nf.htm

1NF:
    Are there any duplicative columns? No. Do we have a primary key?
    ・Eliminate duplicative columns from the same table.
　・Create separate tables for each group of related data and identify each row with a unique column (the primary key).

2NF:
     Are there any subsets of data that apply to multiple rows?
　・Remove subsets of data that apply to multiple rows of a table and place them in separate tables.
　・Create relationships between these new tables and their predecessors through the use of foreign keys.

3NF:
      Are all of the columns fully dependent upon the primary key?
　・Already meet the requirements of both 1NF and 2NF
　・Remove columns that are not fully dependent upon the primary key.