You require the following:
1. Letter stating your salary from your company.
2. Father's passport copy.
3. Your passport copy with RP page.
4. Application form (you'll get that from the emmigration office)
5. Attested marriage certificate (only if you are married)
6. Credit/Debit card with Min.Qr200/- balance.

The procedure:
When you have all the above you go to emmigration office, get the application form filled (Qr.5/-) and go to building 4. Show all the documents at the semi-circular counter and they will give you a token number along with your documents. Wait for you number and when your turn comes submit all the documents at the counter. When they ask for it, give them the card and make the payment. You will get a recipt that has the visa application number on it. Wait for 2 days and print your father's visa from the site (www.moi.gov.qa).

The rest is usual - Flight tickets ect.

Cheers!!