FSW 1
experience in the last ten years in one or more of the occupational categories identified in the Ministerial Instructions.
Note: The list of occupations can be found on our website at: www.cic.gc.ca/english/immigrate/skilled/apply-who-instructions.asp
FSW 2
you have an offer of arranged employment in Canada. The employment offer should be:
in writing,
indeterminate in duration, and
meet the arranged employment factor described in this guide.
FSW 3
you are a temporary foreign worker or an international student residing legally in Canada for at least 12 months immediately before submitting your application.
Note: If you are subject to an enforceable removal order you are not considered to be legally residing in Canada and would therefore not meet the eligibility criteria for this category.
I stongly recommed reading the guide at
http://www.cic.gc.ca/english/pdf/kits/guides/EG7.pdf