First go to this site and see if your Job is given in the List, if not you are not elligible to apply as Federal Skilled worker. But can only apply if you have a Job offer from Canada:
www.cic.gc.ca/english/immigrate/skilled/complete-applications.asp
IF your Job is in the List, then check the below website and see if you have performed 70-80% of the given duties of that particular Job, enter the code you picked from the above List (that represents your job) and enter in the search:
http://www5.hrsdc.gc.ca/NOC/English/NOC/2006/Welcome.aspx
IF you are elligible, then Download and read this guide:
http://www.cic.gc.ca/english/pdf/kits/guides/EG7.pdf
Then take a Test to see if you make the 67 Points:
http://www.cic.gc.ca/english/immigrate/skilled/assess/Education.asp
Then see the Check List for Documents:
http://www.cic.gc.ca/english/pdf/kits/forms/IMM5612E.pdf
This will give you a detailed and clear view of where you stand and what to arrange for.