If you are willing to go Qatar for your job destination then you can apply for the job VISA through various recruiting agency (Manpower) or you can contact directly to the company when there is vacancy announcement from the company.
Hundreds of Qatar job visa are announced everyday, you can read all the job visa from the website which link is posted below. You can get all the latest updated job visa vacancy with the specified position with salary, contract period and other details like lodging and accommodation. sparrowjob.com
But before applying job visa through the Manpower or recruiting agency make sure you have confirmed the job demand from the ministry of foreign employment by confirming the LT Number. By confirming the LT number one can assure about the job vacancy, verified recruiting manpower, company from where the visa has arrived and all other details about fooding, lodging, contract etc.
Basically you will get 2 years validity for your job visa, but you can further extend the visa when you are stable for the particular jobs.
Remember that before giving anyone your passport you conform everything about the Job visa. Do not sign on any paper without knowing all the details about the paper. You may be given fake contract paper or you might be asked to sign forcefully. Be cautious about the abroad visa process. Doing these you will be safe and you can minimise the cost of fake job visa.