If you already done this before, you should have more experience then us as you have already gone through this before. Anyway We can't do thing at your place, go and read the guide and collect all proofs and documents. We can only help you on specific question. This is a forum not a consultant office, we are not here to fill your form. We are here to help each on things we don't understand or are confused and not sure.
So My advise start by reading the guide, start filling forms, start collection docuemnts and then if you need any help about any thing in particular you can come and ask
Here are link to 3 things you will need :
Main Page for sponsoring : http://www.cic.gc.ca/english/information/applications/fc.asp
Sponsor Guide : http://www.cic.gc.ca/english/information/applications/guides/3900ETOC.asp
Sponsored Guide : http://www.cic.gc.ca/english/information/applications/guides/3999Etoc.asp
Main check list for forms and documents needed : http://www.cic.gc.ca/english/pdf/kits/forms/IMM5491E.pdf
Check list for your wife document and proof to provide (for Pakistan) there are some extra form also to fill in there : http://www.cic.gc.ca/english/pdf/kits/guides/3907e.pdf
Good luck