Just download the form from
http://www.moi.gov.qa/site/english/forms/index.html
Select Tourist Visa Application Form from the Category Airport Security and Passport Department.
* Fill the Form
* Attach Passport Copies of your kith and kin (Blood Relation)
* Salary Certificate (They require some time)
* And Proof of Relation - As Marriage Certificate
from the both end if u r going to call ur sister or
brother.

Good Luck