I don't mean to be discouraging but before you come to Qatar you need to do a LOT of research and make a number of contacts in your profession before even landing in Doha, otherwise your time will be wasted. If you need simple advice on cost of living, etc, it would suggest to me that your information gathering has recently begun. Let me jut say that a vast number of job-seekers from Dubai have beat you here and are actively looking for positions and have a lot more local knowledge. Your best bet is a thorough search from your home situation.
Mandi