I have been told that it can take a really long time for your visa application process to clear, but at the last minute you will asked to provide a date of when you will be arriving. Within a week or so! Its best to just spend as much time as you can making sure your flight money is sorted and you are ready to leave with all your stuff and your head in check!
Im just making sure that I try and find out as much as i can about Doha before I go!

Sarah