How is a Msc thesis judged?

I will have to submit my master of science thesis (in the engineering field) in 2 months, therefore I would like to know which aspect of the thesis are taken into account the most in the final evaluation.

Also, is it mandatory for this kind of thesis to have as output a new procedure/methodology? And what if mine doesn't?

What are the main factors that the commission will focus on when deciding the final evaluation of the work done?

Moreover, in my thesis I am appling an already existing method to some numerical and experimental cases. If I find out that the method as some drawbacks which might prevent its use (at least for what has been my experience with it) should I say it in the final comments or should I present my work as successfull as possible not to give a bad idea about what I have done?