Rules of Data Normalization

1NF	Eliminate Repeating Groups - Make a separate table for each set of related attributes, and give each table a primary key.
2NF	Eliminate Redundant Data - If an attribute depends on only part of a multi-valued key, remove it to a separate table.
3NF	Eliminate Columns Not Dependent On Key - If attributes do not contribute to a description of the key, remove them to a separate table.
BCNF	Boyce-Codd Normal Form - If there are non-trivial dependencies between candidate key attributes, separate them out into distinct tables.
4NF	Isolate Independent Multiple Relationships - No table may contain two or more 1:n or n:m relationships that are not directly related.
5NF	Isolate Semantically Related Multiple Relationships - There may be practical constrains on information that justify separating logically related many-to-many relationships.
ONF	Optimal Normal Form - a model limited to only simple (elemental) facts, as expressed in Object Role Model notation.
DKNF	Domain-Key Normal Form - a model free from all modification anomalies.

Important Note! All normal forms are additive, in that if a model is in 3rd normal form, it is by definition also in 2nd and 1st.

http://web.archive.org/web/20080805014412/http://www.datamodel.org/NormalizationRules.html#five

Source: Datamodel.org