For visit visa Profession should be higher than labour in your RP, NOC from Employer, Salary certificate (5K+, I heard that it has been revised to 8K+ but not sure)
Tenancy Contract, Passport copies, Marriage certificate Attested both from your home country and in Qatar (HRD, MEA, Qatar Embassy and in Qatar MOFA, Photos, Degree Certificate Optional

Please check about minimum salary required and let me also know about it.