Hi,

you should bear in mind that not only accommodation, transportation and day to day expenses should be taken into consideration but also annual ticket to your homecountry , performance appraisal schemes, annual bonuses schemes, annual vacation days, etc.. make sure you have a clear and written confirmation regarding all the above (and everything else that you think is still missing ) - as for the salary offered, you could resort to our salaries section on bayt.com to find out approximately what the salary range would be for your specific job in Qatar : http://www.bayt.com/salaries .
Best of luck!